Journals >Spectroscopy and Spectral Analysis
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2020
Volume: 40 Issue 6
56 Article(s)
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Real-Time Measurement of NOy (Total Reactive Nitrogen Oxide) by Cavity Ring Down Spectrometer (CRDS)
WU Sheng-yang, HU Ren-zhi, XIE Pin-hua, LI Zhi-yan, LIU Xiao-yan, LIN Chuan, CHEN Hao, WANG Feng-yang, WANG Yi-hui, and JIN Hua-wei
Nitrogen oxide, being one of an important trace gas in the atmosphere, may affect the oxidation of the atmosphere, harm the physiological health of the human beings and the animals, and cause photochemical smog, haze, acid depositions and other environmental problems. In recent years, with the rapid development of the Nitrogen oxide, being one of an important trace gas in the atmosphere, may affect the oxidation of the atmosphere, harm the physiological health of the human beings and the animals, and cause photochemical smog, haze, acid depositions and other environmental problems. In recent years, with the rapid development of the economy and the continuous increase of energy consumption in our country, the nitrogen oxide emissions have been remaining at a high level. Therefore, it is of great significance to study the content and chemical properties of the nitrogen oxides in the atmosphere. The methods for determining NOx has tended to become diversified. However, the methods for determining the total reactive nitrogen oxide (NOy) have always been dominated by the catalytic conversion chemiluminescence (CL). In this paper, a method of simultaneous measurement of NO2 and NOy concentration in the ambient air by the thermal dissociation cavity ring down spectrometer (TD-CRDS) is introduced. The performance of the pyrolysis device was optimized, the effective absorption cross section of NO2 was determined, the interferences which may possibly exist in the system (H2O, glyoxal, NH3, N2O and etc. ) was analyzed, and the detection limit (NO2 chamber: 8.72×108 molecules·cm-3; NOy chamber: 9.71×108 molecules·cm-3) and the errors (NO2 measurement: 5%; NOy measurement: 12%) were discussed. In order to verify the performance of the system, the concentration of NO2 was determined by comparing the CRDS and the long-path differential optical absorption spectroscopy (LP-DOAS) synchronously, with a linear correlation factor r=0.960. The concentration of NOy in the atmosphere was determined through comparing with the model Model 42i-NOy analyzer synchronously, with a linear correlation factor r=0.968. Both consistencies is good. A field experiment was performed for a week at Hefei Science Island. During the measurement, the average concentrations of NO2 and NOy were 4.11×1012 molecules·cm-3 and 7.73×1012 molecules·cm-3, respectively. According to the average daily variation diagram, it is found that there is a similar trend in the concentration of NO2 and NOy, and it usually starts to decline at 10:00 and the lowest value occurs at 15:00. Because of its high sensitivity and high time resolution, the CRDS has become a new and simple method for determining the total reactive nitrogen oxide in the ambient air..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1661 (2020)
Research on Respond of Water-Soluble Organic Compounds in Atmospheric Particulate to pH Based on Three Dimensional Excitation-Emission Matrix
QIN Yuan-yuan, XIAO Kang, YANG Yan-rong, QIN Juan-juan, ZHOU Xue-ming, GUO Song-jun, CHEN Rong-zhi, TAN Ji-hua, YU Jin-lan, and HE Ke-bin
Three dimensional excitation-emission matrix spectra (3DEEM) is an effective tool for characterizing the chemical composition and functional groups of water-soluble organic compounds (WSOC) in atmospheric particulate, at present, the report of WSOC was analyzed by 3DEEM just in fluorescence intensity and its indices. DThree dimensional excitation-emission matrix spectra (3DEEM) is an effective tool for characterizing the chemical composition and functional groups of water-soluble organic compounds (WSOC) in atmospheric particulate, at present, the report of WSOC was analyzed by 3DEEM just in fluorescence intensity and its indices. Due to the wide range of pH value of atmospheric particulate (0~9), the formation, transmission and transformation of WSOC in atmospheric particulate are easily influenced by pH. Therefore, studying the effect of pH on the fluorescence characteristics of WSOC is important for further understanding the environmental effects and chemical composition of WSOC, however, the effect of pH on the fluorescence characteristics of WSOC has not been reported. On this basis, 3DEEM was used to investigate the fluorescence characteristics of WSOC in PM2.5 in Beijing, and focused on the changes of fluorescence characteristics of WSOC under different pH (2~8). Humic-like, tryptophan-like and freshly produced organic matter were found to be the main fluorescence substances of WSOC in PM2.5. The further studying showed that the fluorescence peak position, fluorescence intensity and fluorescence indices of WSOC were sensitive to pH. The fluorescence intensity reached the maximum when pH was about 3, which may be the result of the maximum carboxyl protonation, the fluorescence intensity showed an opposite trend when the pH was more than 3, and decreased significantly with the increasing pH, which was probably caused from enhanced of hydrogen bonding between intermolecular and intramolecular. In addition, the fluorescence peak of tryptophan-like appeared a slightly red shift with the increasing of pH in summer, suggested the increasing benzene ring and degree of conjugation in the molecular structure of WSOC. Comparing to other fluorescent substances, the humic-like substance was more easily influenced by pH. The statistical correlation analysis between pH and fluorescence indices exhibited seasonal differences in fluorophore structure of WSOC. Biological index (BIX) had a significant negative correlation with pH, and decreased significantly with the increasing of pH. While pH was a significant positive correlation with Peak T/C (the intensity ratio of peak T to peak C) (p<0.01), and Peak T/C increased significantly with the increasing of pH, it indicated that low pH was not conducive to the biodegradation of organic matter. Fluorescence index (FI) and humification index (HIX) increased first and then decreased with increasing of pH, and the range of values varied from 1.6~3.64 and 0.8~1.94, respectively. Through the analysis of 3DEEM, it was found that pH was an important factor affecting the fluorescence characteristics of WSOC, the effect of pH should be considered when characterizing the optical properties or other properties of WSOC..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1668 (2020)
Excited State Dynamics of Bilirubin Dimethyl Ester-Copper Ions Complex
YAN Shu-jun, LIU Yang-yi, HE Xiao-xiao, ZHENG Ming, CAO Xiao-dan, XU Jian-hua, and CHEN Jin-quan
Bilirubin dimethyl ester (BRE) is a linear tetrapyrrole which is an analogue of bilirubin (BR)［1-3］/ There is no significant difference betweenthe UV, IR and MS spectra of BR and BRE. BR/BRE can form complexes with a variety of metal ions. The coordination sites of BR and metal ions are mainly the pyrrole nitrogen, andBilirubin dimethyl ester (BRE) is a linear tetrapyrrole which is an analogue of bilirubin (BR)［1-3］/ There is no significant difference betweenthe UV, IR and MS spectra of BR and BRE. BR/BRE can form complexes with a variety of metal ions. The coordination sites of BR and metal ions are mainly the pyrrole nitrogen, and propionic acid side chains, and the hydroxyl groups of the BR propionic acid side chains couldbe substituted with methyl groups to obtain BRE so that the metal ions only coordinate with the nitrogen on the pyrrole ring. Therefore, we have used esterified bilirubin BRE to study its interaction with metal ions, which has the advantages of reducing the coordination point with the metal, as well as the complexity of the product, and contributing to the spectral analysis. Metal ions have an effect on the fluorescence characteristics of BR/BRE. Unlike the fluorescence enhancement of Zn2+, Cu2+ has an obviousfluorescence quenching on BRE. Studies have shown that hyperbilirubinemia and gallstones are related to BR and copper ions［4-7］. Therefore, studying the interaction of bilirubin and its analogues with Cu2+ is of great significance for the prevention and treatment of these diseases. When linear tetrapyrrole molecules coordinate with metal ions, they generally transform from the original chain structure to a porphyrin-like ring structure to suit the coordination with the central ion, a copper ion and the four central pyrrole nitrogens on a BR/BRE molecule coordinate to form a metal-centre square planar structure (Fig.1). BRE itself has a relatively low fluorescence quantum yield because the vibration of the pyrrole ring causes some excited molecules to decay to the ground state in a non-radiative manner[8]. Coordination of Cu2+ with BRE may cause their energy levels to couple to generate a new non-radiative de-excitation pathway leading to a decrease in fluorescence, but further research is needed on the quenching mechanism of Cu2+ on BRE fluorescence. The de-excitation processes of the excited state molecules generally occur on the ultra-fast time scale, which cannot be observed by the traditional steady-state spectroscopy. The visible and infrared-band femtosecond transient absorption spectroscopy techniques were used to study the excited state spectral properties of BRE-Cu2+ complex in this paper. A new quenching mechanism of Cu2+ on the BRE flurescnece was discovered by the transient absorption spectrain the visible and infrared region. We have proposed and confirmed the Ligand-to-metal charge transfer (LMCT) as a result of the fluorescence quenching. Compared with the spectral properties of BRE, the charge transfer state would provide a non-radiative decay pathway to BRE-Cu2+ complex, reducing the fluorescence quantum yield of BRE to 5% of its original value. Moreover, two lifetimes (11 ps and 186 ps) were obtained by fitting the kinetic curves of the transient absorption spectra of the complex. We assign the 11 ps component to the build-up process of the LMCT state, while the 186 ps is the lifetime of the charge transfer state..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1674 (2020)
D-Shaped Divided Aperture Confocal Brillouin Microscopy
WU Han-xu, NING Ying, QIU Li-rong, WANG Yun, and ZHAO Wei-qian
Confocal Brillouin microscopy (CBM) provides a non-contact, non-destructive, and high spatial resolution measurement, which has widely been applied in biomedical detection, physical chemistry, and materials science. The Brillouin scattering frequency is low, and the intensity is weak, so the signals can be easily overlConfocal Brillouin microscopy (CBM) provides a non-contact, non-destructive, and high spatial resolution measurement, which has widely been applied in biomedical detection, physical chemistry, and materials science. The Brillouin scattering frequency is low, and the intensity is weak, so the signals can be easily overlapped or even overwhelmed in the case where the elastically scattered light is not sufficiently suppressed, which significantly limits measure accuracy of the Brillouin spectrum. In addition, the spectral axial resolution and tomography ability of CBM is still insufficient, which limit applications in the fields of high scattering samples and large working distance. In this paper, a D-shaped divided aperture confocal Brillouin microscopy (DDACBM) is proposed to improve the anti-elastic scattering ability, spectral axial resolution, and tomographic capability of CBM. DDACBM eliminates the backscattering light and reduces the crosstalk between the elastic scattering and Brillouin scattering by symmetrical lateral offset illumination and lateral offset detection.Thus the anti-elastic scattering ability of CBM is improved. And the point spread function of the illumination light path and the collection light path is modulated. The illumination light path and the collection light path only overlap on the focal plane by the inclined incident. Therefore, threedimensional point spread function is compressed in the z-axis, and the interference between the defocused plane and the focal plane is effectively removed. The full width at half maximum and a full maximum of the axial spectral intensity response curve reduce, thereby the spectral axial resolution and tomography ability of the CBM are improved. Experiments show that DDACBM improves the anti-elastic scattering ability and tomographic capability of the CBM. And by optimizing the pupil parameter, the spectral axial resolution is improved by more than 30%, which can effectively reduce the spectral crosstalk in multi-layer samples. DDACBM provides a guarantee for further applications of Brillouin spectrum technology in the modern basic research fields..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1679 (2020)
Temperature Measurements of Inductively Coupled Plasma Spheroidization by Using Argon Emission Spectroscopy
ZENG Hui, and OU Dong-bin
Inductively coupled plasma (ICP) reactor is able to generate pure thermal plasma and realize sphericalization process of irregular powder particles by joule heating, demonstrating great application prospect in the aerospace industry. Gas temperature is a crucial parameter for inductively coupled plasma spheroidization.Inductively coupled plasma (ICP) reactor is able to generate pure thermal plasma and realize sphericalization process of irregular powder particles by joule heating, demonstrating great application prospect in the aerospace industry. Gas temperature is a crucial parameter for inductively coupled plasma spheroidization. Spatial resolved temperature measurement of the high-temperature flow field in the plasma reactor provide quantitatively basis and evidence for theoretical study of plasma spheroidization and industrial methodology optimization. It leads to research gap in flow diagnostics for high-temperature inductively plasma flow owing to the inapplicability of conventional diagnostic techniques. This paper presents in-situ and non-intrusive diagnostics for argon plasma flow in the inductively coupled plasma spheroidization based on optical emission spectroscopy. Spatial-resolved gas temperature in the radial coordinate was measured at a cross section under the powder feed gun by combining argon emission spectroscopy and electric-driving scanning technique. The measured results show that gas temperatures in the radial coordinate showed a saddle-shape trend under no powder-in conditions and the temperature value in the center was (10 120±240) K, while the maximum temperature zone was positioned close to the core with specific values of (10 500±240) and (10 620± 240) K, respectively. There existed obvious temperature difference at the measured cross section under powder -in and no powder-in conditions. A maximum temperature difference under the two conditions was observed to be nearly 500 K and 400 K in the core and the maximum temperature zone respectively, indicating temperature drop of plasma flow when the injected particles were heated. The developed technique in this paper provide a mature method to quantitatively understand the two-dimensional spatial distribution of gas temperature in the inductively plasma spheroidization reactor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1685 (2020)
Correction of Temperature Influence in Near Infrared Spectroscopy
SUN Yan-hua, and FAN Yong-tao
For the problem that the temperature change of the sample affects the prediction result of the model, firstly, the spectrum of the same sample at different temperatures is compared with the spectrum of the same sample at the same temperature. The results show that the spectral difference at different temperatures is laFor the problem that the temperature change of the sample affects the prediction result of the model, firstly, the spectrum of the same sample at different temperatures is compared with the spectrum of the same sample at the same temperature. The results show that the spectral difference at different temperatures is large. Then the effect of sample temperature on the prediction of corn crude protein model was studied. Spectral collection of samples with a crude protein content of 6.04% was performed at different temperatures, and near-infrared spectra at different temperatures were pretreated in the same way as those used in modeling, so as to eliminate the influence of factors other than the temperature on the spectra. The pre-processed spectrum is substituted into the established model for prediction. The prediction results show that the difference between the predicted result and the measured value increases as the difference between the spectral temperature and the modeled temperature increases, and the maximum error is 1.12%. In order to solve the influence of temperature on the prediction results of the model, we further analyzed the relationship between temperature and spectral data at different temperatures, and found that after removing the areas with serious noise at both ends of the spectrum, there was a certain linear relationship between spectral data at the same wavelength point at different temperatures. According to this finding, a temperature correction theory is proposed. Taking the spectrum at the time of modeling as the reference spectrum, and then using the linear regression algorithm to perform linear regression on the spectra of different wavelength points according to the linear relationship between temperature and spectrum, the difference between the spectrum at different temperatures and the reference spectrum is obtained. Finally, the spectra at different temperatures are corrected to the reference spectrum. After the spectrum is corrected by the theory, the difference between the spectra has been greatly improved compared with before the correction. The corrected spectrum is brought into the model, and most of the prediction results are improved, which meets the requirements of ±0.5% of the national standard. Finally, the temperature correction theory was verified by using 34 different samples unrelated to the modeling. The model prediction values and standard physical and chemical value determination coefficients of the crude protein before and after the spectral correction were 0.910 and 0.982, respectively, and the root means square error was 0.558 and 0.172, and the average relative error was 6.05% and 1.75%, respectively. The temperature correction theory has been temperature-corrected from the nature of near-infrared spectroscopy, providing a reference for temperature correction of other samples, which is beneficial to the promotion of handheld near-infrared spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1690 (2020)
Inversion Research on Dust Distribution of Urban Forests in Beijing in Winter Based on Spectral Characteristics
SU Kai, YU Qiang, HU Ya-hui, LIU Zhi-li, WANG Peng-chong, ZHANG Qi-bin, ZHU Ji-you, NIU Teng, PEI Yan-ru, and YUE De-peng
Urban forests affect the filtration and adsorption of airborne particulate matter, which can minimize the harmful effects on human health caused by airborne particulate pollution. Evergreen plants in urban forests play a major role in absorbing dust and purifying the air, especially in winter. In this study, Euonymus jUrban forests affect the filtration and adsorption of airborne particulate matter, which can minimize the harmful effects on human health caused by airborne particulate pollution. Evergreen plants in urban forests play a major role in absorbing dust and purifying the air, especially in winter. In this study, Euonymus japonicus, the main evergreen vegetation in winter in Beijing, was used as the research object. Three types of sampling space were set up, and 1 410 leaves were collected to measure the hyperspectral data before and after cleaning and the amount of dust absorption (ADA) on the surface of the leaf. The sensitive band was determined by analyzing the response of spectral reflectance to the amount of dust retention, and the regression model was established between the vegetation index ratio and ADA before and after cleaning. The Sentinel-2 remote sensing image was used to obtain the dust distribution of the evergreen vegetation, and the inversion results were verified. The result showed that in the range of 510～700 and 758～1 480 nm, the average spectral reflectance of the blade before dust removal is less than that of the clean blade. The change of average spectral reflectance before and after cleaning in the closed zone is less than that in the semi-closed zone, and the change in the open zone is the largest. And the red band and nearinfrared band are most sensitive to dust. The inversion model established using the Normalized Difference Phenology Index (NDPI) is: x=0.939 69y-0.145 04(x represents the value of RNDPI, and y represents the amount of dust retention), and the determination coefficient (R2) reached 0.879. The inversion results show that the mean ADA in the enclosed area is smaller than that in semi-enclosed and open areas, and the regional distribution of high ADA in the urban area of Beijing was higher in the south with a tendency of the ADA to decrease from city centre to the surrounding area. Study the spatial distribution of leaf dust retention and provide a reference for rapid monitoring of dust pollution intensity and distribution in urban areas, and exploring the dust retention effect of evergreen shrubs are important for scientifically guiding urban forest construction and improving the living environment of cities in winter..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1696 (2020)
Methane/Air Coaxial Jet Flame Reaction Heat and Quantitative Characterization of OH*/CH*
ZHANG Lang, TAN Jiang-guo, and LIU Yao
Excited particle is a natural tracer of the chemical reaction process, but the research on the excited particle is mainly carried out under simple one-dimensional flame. In order to investigate the distributions excited state under complex conditions of chemical reaction heat quantitative characterization of rule, the Excited particle is a natural tracer of the chemical reaction process, but the research on the excited particle is mainly carried out under simple one-dimensional flame. In order to investigate the distributions excited state under complex conditions of chemical reaction heat quantitative characterization of rule, the methane/air coaxial jet diffusion flame test has carried out detailed ground state and excited of methane/air premixed flame burning mechanism of coaxial jet diffusion flamen and numerical simulation, analyzes the distribution characteristics of OH* and CH*, the excited state is studied on the relationship of the heat of reaction. The results showed that the chemiluminescence diagram of OH* and CH* obtained by ICCD camera and corresponding filter and the simulated results of the mole fraction distribution of OH* and CH* in the numerical were consistent. The OH* distribution was mainly divided into three combustion regions, and the CH* distribution was mainly divided into two combustion regions. The distribution of OH* and CH* in the diffusion flame presents a single peak, and the reaction heat presents a bimodal phenomenon. The changing trend of the reaction heat is similar to that of the excited state. After reaching the first peak, the exciter state gradually decreases to zero, while the reaction heat first decreases and then slowly increases to the second peak, and finally reduces to zero. In the diffusion flame, when the mass fraction of OH* and CH* in the radial direction reaches the peak, the heat of reaction also reaches the first peak. In the axial direction when the reaction rate of C2H+O=CH*+CO(R12) reaches the peak, the heat of reaction reaches the second peak. In premixed flames, with the increase of local equivalent ratio, the mass fraction of OH* and CH* increases obviously, and the distribution area is wide. When the mass fraction of OH* and CH* in the radial direction reaches the peak, the heat of reaction also reaches the peak. In the axial direction, the peaks of the four reactions rates of OH* and CH* are all in the same position, and the heat of reaction also reaches the maximum. The reaction rates of CH+O2=OH*+CO(R1) and C2H+O=CH*+CO(R12) are faster than that of H+O+M=OH*+M(R2) and C2H+O2=CH*+CO2(R11)..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1703 (2020)
Study of Inclusion Characterization Method in IF Steel Based on the Spark Source Original Position Statistic Distribution Analytical Technology
LI Dong-ling, ZHAO Lei, SHEN Xue-jing, and WANG Hai-zhou
IF steel has been widely used in the field of automobile and appliance panel with the strict demand for surface quality. The existence of inclusion will greatly affect the surface quality and the performance of cold rolled sheet of IF steel. It is necessary for the IF slab to get rid of the surface layer contained a loIF steel has been widely used in the field of automobile and appliance panel with the strict demand for surface quality. The existence of inclusion will greatly affect the surface quality and the performance of cold rolled sheet of IF steel. It is necessary for the IF slab to get rid of the surface layer contained a lot of inclusions. Because of the different manufacturing technology, there is a lot of uncertainty about the quantity, composition, and size distribution of inclusions in the surface of IF steel which is influenced by somereasons, such as insufficientfloating of the inclusions under the process of cast starting and slag involvement by pool level fluctuation under the acceleration process of the continuous casting machine.It is very important for the discovery of inclusion distribution rulein different depth beneath the surface of IF steel slab, identification of suitable cutting thickness in the slab surface and the inclusion control in a crystallizer to study the inclusion distribution characterization method in detail.Metal original position statistical distribution analytical technique can be used for the determination of inclusion content and size distribution within a large scale of the section by the high-speed data acquisition and analysis of spectrum signals excited by spark discharge with the mode of no pre-spark and continuous excitation on the scanning process. In this paper, the abnormal discharge behavior of inclusions in IF steel has been investigated and the suitable reference material of particle size distribution for IF steel was developed. The relationship of the abnormal spectrum signals produced by Al element with the size distribution of oxide inclusion was also discussed based on the spark source original position statistic distribution analytical technique combined with scanning electron microscope and energy dispersive spectrum. It was found that the linear correlation coefficient of the binary linear regression equation between the net intensity of the abnormal signal of inclusion components and the particle size of inclusion was good with the value above 0.99. So the inclusion characterization method of composition, content and size distribution in IF steel based on the spark source original position statistic distribution analytical technology has been developed. The variation rule of inclusion composition, content and size distributionin the depth of 0~3 mm beneath the surface of IF steel outer arc has been studied.It was found that the inclusion in IF steel consisted of two kinds of inclusions. One is the single inclusionof aluminum oxide produced in the deoxidization process. The other is the complex inclusion of AL, CA and Si produced by the slab involvement.The inclusion content in the depth of 0.5 and 1.0 mm beneath the surface was lower than the content from the depth of 1.5 to 2.5 mm beneath the surface. There were more complex inclusion of Al and Ca with a larger average particle size existed indepth from 1.5 to 2.5 mm beneath the surface, and the particle size decreased when the depth beneath the surface increase to 3 mm. It is of great importance for the technicalguidance of IF steelmanufacturing..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1710 (2020)
The Hypothesis of Medicinal Gypsum Cooling Material
SONG Chen, ZHANG Zhi-jie, and BIAN Bao-lin
Clinical Chinese Medicine commonly used gypsum (CaSO4·2H2O) to treat febrile diseases. Based on the study of microscopic crystal characteristics and trace element characteristics of gypsum, the hypothesis that trace element strontium (Sr) is an important influential element for gypsum cooling is proposed. We analyClinical Chinese Medicine commonly used gypsum (CaSO4·2H2O) to treat febrile diseases. Based on the study of microscopic crystal characteristics and trace element characteristics of gypsum, the hypothesis that trace element strontium (Sr) is an important influential element for gypsum cooling is proposed. We analyzed the microscopic crystal structure and trace element composition of 33 batches of gypsum herbs from five producing areas by optical polarized light microscopy (OPLM), X-ray diffraction (XRD), electron probe micro-analysis (EPMA) and inductively coupled plasma mass spectrometry (ICP-MS). The results of OPLM analysis show that the microscopic morphology of gypsum is mainly long columnar and fibrous, and is related to the original area of gypsum. According to the traditional requirements, the samples with good quality have larger micro-particles. XRD analysis showed that except for one batch of samples containing quartz impurities, the other samples showed no other mineral impurities. The results of EPMA analysis showed that the main mineral in the gypsum sample was gypsum and the secondary mineral was anhydrite, which showed a symbiotic relationship. The anhydrite in the micro-area image has no definite crystal form, and the contact surfaces of anhydrite and gypsum are irregular curves. It is speculated that the anhydrite is converted from the gypsumin the later stage of mineralization rather than native. The results of ICP-MS analysis showed that the trace element strontium (Sr) was higher in gypsum, and the highest absolute content of all trace elements. The comparison with trace elements in the primitive mantle showed that the Sr element is the most stable and enriched trace element in the gypsum sample, which is more than 6 times more than the primitive mantle, up to 176 times. The analysis of the value of CaO/SrO in the micro-site of gypsum shows that the strontium (Sr) element is statistically uniformly distributed in the gypsum and exists mainly in the form of isomorphic mixtures in gypsum. The results of the determination of the Sr element content in the aqueous gypsum solution showed that the dissolution amount of strontium (Sr) in the gypsum decocted fluid and the gypsum suspension reached 2～4 times of the theoretical value. Gypsum was used in large doses in the clinic, and decocted first can promote the dissolution of Sr2+. Because Sr has the effect of inhibiting Na. The hypothesis of gypsum cooling: when gypsum is used for cooling, Sr2+ and Ca2+ are simultaneously dissolved. Sr2+ inhibits the absorption of Na+ to the body, increases the supply of Ca2+ to the body, and regulates the ratio of Na+/Ca2+ one of the positive regulation medium of fever. The material basis for the cooling of gypsum is the joint action of Sr and Ca..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1716 (2020)
Determination of the Oxidizability on the Surface of the Graphene Oxide Layer by Infrared Spectroscopy
WEI Gang, GU Zheng-ye, GONE Shui-shui, GUANG Shan-yi, KE Fu-you, and XU Hong-yao
Graphene oxide is composed of sp2 and sp3 hybrid carbon atoms and contains a plurality of oxygen-containing groups of hydroxyl, epoxy and carboxyl groups, and which is the precursor of many functionalized graphenes. The hydroxyl group is mainly on the surface of the graphite sheet, and the carboxyl group is mainly locaGraphene oxide is composed of sp2 and sp3 hybrid carbon atoms and contains a plurality of oxygen-containing groups of hydroxyl, epoxy and carboxyl groups, and which is the precursor of many functionalized graphenes. The hydroxyl group is mainly on the surface of the graphite sheet, and the carboxyl group is mainly located at the edge of the sheet structure. An ordered composite material perpendicular to the surface, and a functional composite of various overhanging structures can be obtained by the hydroxycarboxyl group of graphene oxide. The performance of functional graphene varies greatly depending on the degree of oxidation. According to the literature, scientists have studied the ratio of different carbon atoms and oxygen atoms in graphene by XRD, XPS, FT-IR, Zeta, Raman spectroscopy, etc., but almost no reports can directly measure the oxygen-containing functional groups on graphene oxide. A method for measuring hydroxyl content of graphene oxide by infrared spectroscopy was set up by using phenol as standard substance, Graphene oxide (GO) was prepared by the method of a chemical oxidation-reduction reaction, then using phenol as standard substance measured the hydroxyl content since phenol and GO have similar skeletal structure. The spectrum of phenol illustrated the peaks of a benzene ring frame vibration (1 597, 1 500 and 1 474 cm-1), the benzene ring C-H in-plane bending vibration absorption peak (1 692 cm-1), and the C-OH stretching vibration absorption peak of phenols (1 234 cm-1), while the spectrum of GO illustrated the peaks of CC stretching vibration (1 630 cm-1) and C-OH stretching vibration (1 400 cm-1). Thus, with the ratio of peak area of a benzene ring or C-OH of both phenol and GO, hydroxyl content of graphene oxide sheets was calculated by structural analogy analysis and correlation formula. The analogy infrared spectroscopy method could be applied to estimate the oxygen or hydroxyl content on the surface of graphene oxide sheets. Field emission scanning electron microscopy, Transmission electron microscopy, Atomic force microscopy, UV-visible spectrophotometer and Laser Raman spectroscopy were used to further verify the rationality of the above method..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1722 (2020)
Review on the Application of Micro-X-Ray Fluorescence Analysis Technology in China
WANG Yi-ya, WANG Yi-ming, DENG Sai-wen, GAO Xin-hua, LIANG Guo-li, and ZHANG Zhong
The technical characteristics, instrument composition, application fields and working scope of X-ray fluorescence (XRF)and micro-X-ray fluorescence analysis (MXRF)are briefly described. The development of micro-X-ray fluorescence instruments and analytical techniques in China is reviewed from four aspects: collimated mThe technical characteristics, instrument composition, application fields and working scope of X-ray fluorescence (XRF)and micro-X-ray fluorescence analysis (MXRF)are briefly described. The development of micro-X-ray fluorescence instruments and analytical techniques in China is reviewed from four aspects: collimated microbeam X-ray fluorescence instrument, integrated X-ray fluorescence and micro-X-ray fluorescence instrument, micro-X-ray fluorescence function in multifunctional (spectrum/energy spectrum) instrument and capillary X-ray convergent lens micro-X-ray fluorescence instrument. Finally, the development of micro-X-ray fluorescence technology has prospected from two aspects of functional positioning and technological development. It is proposed that the traditional in-situ microanalysis can be further divided into “μ-n(area)-analysis(μ-XRF)” and “sub-mm-cm(area)-analysis(MXRF)”. This kind of technical distinction and application scope positioning is beneficial to the development of in-situ microanalysis technology, and also provides a clear positioning for the development and application of integrated/micro-zone combination instruments. The author also emphasizes that in-situ microanalysis is not a simple analytical problem, but more importantly, the study of the properties of the tested materials and the reasonable interpretation of the results. Close cooperation between analytical technicians and professional scientists can give full explain to the effectiveness of in-situ analytical techniques and analyze the scientific significance of analytical results in detail..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1728 (2020)
Application of Fluorescence Spectroscopy in Identification of Aromatic Components in Single Oil Inclusions
SI Shang-hua, ZHAO Jing-zhou, ZOU Guo-liang, LIU Fei, LIU Chao, and YAN Guan-yu
In order to clarify the relationship between aromatic hydrocarbon components and micro-fluorescence spectra in oil inclusions, based on the fluorescence property of oil, the fluorescence spectra of oil inclusions in Gaotaizi reservoir in Qijia area of Songliao Basin were quantitatively described by non-destructive analIn order to clarify the relationship between aromatic hydrocarbon components and micro-fluorescence spectra in oil inclusions, based on the fluorescence property of oil, the fluorescence spectra of oil inclusions in Gaotaizi reservoir in Qijia area of Songliao Basin were quantitatively described by non-destructive analysis of single inclusion components. Firstly, the fluorescence color types of oil inclusions in reservoirs were obtained, and then the fluorescence spectra of single oil inclusions were obtained. The main peak wavelength characteristic values of standard aromatics under 365 nm monochrome light excitation were compared. Finally, the hydrocarbon charging episodes and the types of aromatics in different episodes of oil inclusions were classified. The results show that there are three kinds of fluorescent oil inclusions: yellow, yellow-green and blue-green, which represent hydrocarbons charging with different maturity. The main aromatic components in oil inclusions are benzotetraphenyl, decacyclene and benzophenanthrene, followed by bilianthracene and a small amount of pentacene and red fluorene. Among them, the aromatic components in the first screen oil inclusion are pentacene, benzotetraphenyl, red fluorene and decacyclene; the aromatic components in the second screen oil inclusion are mainly benzotetrabenzene, decacyclene, benzophenanthrene and a small amount of red fluorene; and the third screen oil inclusion is benzophenanthrene. The main aromatic hydrocarbon components are benzotetraphenyl, decacyclene and benzophenanthrene, followed by bilianthracene. According to the types of aromatic hydrocarbon components, there are more high molecular weight aromatic hydrocarbons in Episode 1 than in Episode 2 and episode 3, showing lower maturity, while there are more types of small molecular aromatic hydrocarbons in Episode 2 and episode 3, showing medium maturity. Reservoir oil inclusions generally show fewer aromatics of small molecular weight and more aromatics of large molecular weight, which indicates that crude oil has undergone biodegradation and water washing before being captured by inclusions, and has undergone overheating and metamorphism after capturing. Crude oil in reservoir inclusions mainly consists of low-to medium-maturity crude oil. Finally, the relationship between the fluorescence spectrum characteristics of oil inclusions and the aromatics components is drawn up, which provides a basis for the study of the types and maturity of aromatics components in crude oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1736 (2020)
A Piecewise Mathematical Model for COD Measurement of Water by UV Spectrometry
TIAN Guang-jun, XU Guang-yao, and TIAN Qing
The relationship between the UV absorbance and the COD significantly deviate from the linear relationship when the samples reach a certain concentration(still within the concentration range where Lambert-Beer’s law is often applied)when using UV spectroscopy to analyze COD in water, this phenomenon has been mentioned iThe relationship between the UV absorbance and the COD significantly deviate from the linear relationship when the samples reach a certain concentration(still within the concentration range where Lambert-Beer’s law is often applied)when using UV spectroscopy to analyze COD in water, this phenomenon has been mentioned in many scholars’ literature on UV spectroscopy. In thisregard, the S2000 micro-fiber spectrometer and the PX-2 pulsed xenon lamp of Ocean Optics were selected for experiments in a dark room with a temperature of 20 ℃(±0.5 ℃) and humidity of 35%(±5%),andUV absorption spectra of 34 groups of potassium hydrogen phthalate solutions with COD values of 40～680 mg·L-1 were measured for analytical modeling. The dominant wavelength band was selected by correlation coefficient method combine withthe UV absorption characteristics of the sample, and the dominant wavelength was determined to be 275 nm after compared the dynamic characteristics of the COD-absorbance curves at the second characteristic peak of the ultraviolet absorption spectrum of the sample with the wavelength commonly used in water quality COD analysis. A point-by-point extension method is used, which select robust linear regression and the unary nonlinear least squares regression in low concentration segment and higher concentration segment, respectively, repeated fitting of linear or exponential equations and sliding prediction of the next data point,and the segmentation points of the COD-absorbance relationship model of the low concentration segment and the higher concentration segment are determined to be 300 and 560 mg·L-1, respectively, according to the root mean square error and the relative error,and a low concentration segment model and a higher concentration segment model were obtained. The comparison of the fitting accuracy of the linear or nonlinear model in a low concentration range, higher concentration range and the full concentration range at the dominant wavelength indicates that the linear-exponential segmentation model for the relationship between absorbance and COD of water quality in the range of 40 to 300 mg·L-1 and 300 to 560 mg·L-1 has the highest precision, and the prediction effect on the prediction set samples is better: the prediction root mean square error of the model at low concentration is 4.944 9, 6.768 9 at higher concentration and 5.664 7 overall, the prediction effect is ideal for the prediction set. The research result provides a reference value for the measurement and analysis of water with higher COD by UV spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1741 (2020)
The Laser-Induced Fluorescence Spectrum of Gold Monoxide (AuO): b4Π3/2－X2Π3/2 Transition
XIANG Qian-lan, YANG Jie, HUA Xue-xia, ZHANG Ji-cai, and MA Xin-wen
Studying Au-O bond can provide an insight into the rapidly expanding field of gold chemistry. AuO is the simplest model containing Au-O bond. So, it is of great scientific significance to study the electronic structure of gold oxide molecule. Laser induced fluorescence spectroscopy is an effective means to study molecuStudying Au-O bond can provide an insight into the rapidly expanding field of gold chemistry. AuO is the simplest model containing Au-O bond. So, it is of great scientific significance to study the electronic structure of gold oxide molecule. Laser induced fluorescence spectroscopy is an effective means to study molecular structures and chemical bonds. In this paper laser ablation combined with ultrasonic jet technology was used to produce gas phase gold monoxide, and the electronic spectrum of the gaseous gold monoxide molecule (AuO) had been investigated in the range of 16 500～18 500 cm-1 using laser induced fluorescence spectroscopy. The ablation laser (Leibao Dawa-300) sputtered pure gold target (99.9%) which was controlled by a vacuum motor for rotation to produce Au atoms. The pure high pressure O2 was injected into the vacuum chamber through a molecular beam pulse valve (Parker, General Valve, series 9) to react with the gold vapor to form AuO. A dye laser (Sirah, Cobra-Stretch) was pumped by Nd∶YAG laser (Continuum Surelite II-10) and the output of the pulsed dye laser (linewidth 0.05 cm-1, pulse duration 5 ns, energy 0.1 mJ·pulse-1) was introduced into the vacuum chamber to excite AuO. The fluorescence from the excited AuO radical was imaged through appropriate low-pass cutoff filters into a photomultiplier tube (PMT) detector (EMI, ET9202QB). Pulsed analog signals from the PMT were converted into digital signals by a fast digital oscilloscope card (Picoscope 6404C, 500 MHz, 14 bits) and recorded by a data acquisition program based on LabVIEW of our own. The detected bands with band heads at 17 152.94, 17 552.17, 17 932.78 and 18 291.62 cm-1 were attributed to b4Π3/2 (v′=0, 1, 2, 3)－X2Π3/2(v″=0) transitions. The molecular constants including rotational constants and centrifugal distortion constants were determined by analyzing the rotationally resolved spectra. The possible electronic configuration of the excited state is 1σ21π41δ42σ12π33σ*1..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1747 (2020)
Spectroscopic Techniques for Detection of Mycotoxin in Grains
GUO Zhi-ming, YIN Li-mei, SHI Ji-yong, CHEN Quan-sheng, and ZOU Xiao-bo
China is one of the countries with serious concerns about mycotoxin contamination of agricultural food and feed commodities in the world. Mycotoxin contamination leads to a substantial economic loss of grain and oil products coupled with public health hazards; hence, the rapid detection and control of mycotoxin are immChina is one of the countries with serious concerns about mycotoxin contamination of agricultural food and feed commodities in the world. Mycotoxin contamination leads to a substantial economic loss of grain and oil products coupled with public health hazards; hence, the rapid detection and control of mycotoxin are imminent. The traditional wet chemical detection methods cannot meet the needs of rapid and real-time detection in the process of grain production, supply, distribution, and processing. Even though classical techniques such as HPLC are accurate and sensitive, they have the disadvantage of being time-consuming, entail complex sample preparation, expensive and consume large volumes of chemical reagent. Molecular spectrum is the spectral response produced by the transition between the vibrational or rotational energy levels of molecules, which interprets the structural information of molecules. It can determine the rotary inertia, band length, bond strength, and dissociation energy of molecules, and can be used for the detection of chemical components and properties in samples. The light produced by the transition of the molecules of mycotoxin contaminated grain sample under the excited state is acquired by the photodetector through the optical path system. The spectral intensity and the concentration of the tested substance are underpinned by the Lambert-Beer law within a certain range, which can realize the rapid and quantitative detection of mycotoxin in grain. Compared with the traditional methods of fungal toxins detection, spectral analysis technologies have significant technical advantages of rapid, non-destructive and green. The importance and urgency of mycotoxin detection in grain were analyzed, and then the technical principle and theoretical basis of spectral analysis techniques employed for the detection were introduced. Near-infrared spectroscopy is the vibration caused by the change of electric dipole moment, Raman spectrum responses to the vibration caused by molecular polarization, while the fluorescence spectrum reflects the molecular information with long conjugated structure. Spectral imaging expands from one-dimensional to two-dimensional distribution in detection, and detects mycotoxin quickly and accurately by spectral and feature analysis. This work analyzed the research progress and development trend of different spectral analysis technology, and also exposed the advantages and disadvantages of each technique. The investigation revealed the increasing researchers focus on this research field, and the detection and exploration of grain mycotoxin based on spectral analysis technology, which has become a research hotspot of food safety. Through literature review, it can be found that spectral analysis technology provides a novel approach for rapid screening, qualitative identification, or high-sensitivity detection of mycotoxin in food, but there are still many problems that need to be solved. The applications along with major barriers and limitations of these spectral techniques are discussed, with emphasis on the development of recognition, accuracy and stability. Spectroscopic techniques have the potential to fulfill the need for mycotoxin detection. However, they still require enhancement of theory interpretation, detection scale and accuracy. We believe this review will be an effective guide for rapid detection of mycotoxin in the grain to provide a methodological reference..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1751 (2020)
Tri-Wavelength UV Spectroscopy Method by Figuring out the Isobestic Points Shift for the Determination of Fluorescent Whitening Agents in Paper Products
HE Zhi-heng, XU Rong, LIN Jun-feng, YAN Ning, CHEN Chun-xia, CHEN Run-quan, and CHAI Xin-sheng
In the current GB/T 27741-2018 “Paper and board-Determination of migratable fluorescent whitening agents (FWAs)” when extracting paper products, the residual lignin leached from cellulose which would interferespectral detection of FWAs. In this paper reported a tri-wavelength UV spectroscopy method for the determinatioIn the current GB/T 27741-2018 “Paper and board-Determination of migratable fluorescent whitening agents (FWAs)” when extracting paper products, the residual lignin leached from cellulose which would interferespectral detection of FWAs. In this paper reported a tri-wavelength UV spectroscopy method for the determination of FWAs in paper products. By figuring out the isosbestic points shift at the range of 321～374 nm, the spectral interference of other species in the extraction solution on the FWAs measurement can be mathematically corrected. The results showed that the present method has the relative standard deviation of 3.7% and recovery of 99.1 and 107%, with the limit of the quantity of 19 mg·kg-1. Compared with the current FWAs detection method, the method has the advantages of simple analysis, easy operation of the instrument, and the like. Therefore, it is suitable for rapid and accurate determination of the content of migratable FWAs in various paper products, especially printing related materials and can guarantee the production quality control and market supervision of paper products..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1758 (2020)
Pattern Recognition of Traditional Chinese Medicine Property Based on Three-Dimensional Fluorescence Spectrum Characteristics
FAN Feng-jie, XUAN Feng-lai, BAI Yang, and JI Hui-fang
As three-dimensional fluorescence spectroscopy has many advantages, such as good selectivity, high sensitivity, fast analysis, it has been widely used in many fields．As one of the characteristics of traditional Chinese medicine(TCM), Chinese herbal medicine property (CHMP) is the core of TCM. Objective discrimination oAs three-dimensional fluorescence spectroscopy has many advantages, such as good selectivity, high sensitivity, fast analysis, it has been widely used in many fields．As one of the characteristics of traditional Chinese medicine(TCM), Chinese herbal medicine property (CHMP) is the core of TCM. Objective discrimination of the properties of TCM is the key issues of modernization of TCM. The identification of traditional Chinese medicine property is of great significance in the theoretical study of Chinese medicine. Most of the molecules in traditional Chinese medicine have the ability to generate fluorescence. According to the characteristics of the three-dimensional fluorescence spectrum of traditional Chinese medicines, the classification and recognition were studied from the perspective of the properties of traditional Chinese medicines. Firstly, the three-dimensional fluorescence spectral data of 5 different concentrations of 23 cold and warm Chinese medicinal solutions were acquired by FS920 fluorescence spectrometer. Then, the ensemble empirical mode decomposition (EEMD) algorithm is applied to denoise the spectrogram, based on the analysis of noise in different excitation and emission wavelength ranges of different samples. Based on the local linear embedding (LLE) algorithm, feature extraction of spectral data is carried out. The extracted eigenvectors are input into the random forest (RF) to construct LLE-RF classification model. The classification effect of LLE-RF classification model on fluorescence spectrum data of cold and warm Chinese medicines was analyzed under different parameters. The sample ratio of the training set and test set in RF classifier is set to 3∶1 and 2∶1. The correct rate of LLE classification is analyzed when the nearest neighbor points k is 7～18 and the eigenvalue dimension d is 6, 7, 8, 9 and 10. When the nearest neighbor points k is 12 and the eigenvalue dimension d is 7, the accuracy of LLE-RF model for classification of Chinese herbal medicines was 96.6%. Finally, the classification effect of SVM classifier constructed with different kernels on fluorescence spectrum data of cold and warm Chinese medicines was compared under the same ratio of r. When multi-layer perceptron is used as the kernel function, the classification effect is the worst. When r=3/4 and radial basis function is used as the kernel function, the classification accuracy is 82.1%. The results show that the method of combining fluorescence spectroscopy with LLE-RF can effectively recognize cold and warm Chinese medicines, and the classification effect is better than LLE-SVM..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1763 (2020)
Mixed Oil Detection Based on 3D Fluorescence Spectroscopy Combined with AWRCQLD under Different Salinity Conditions
KONG De-ming, DONG Rui, CUI Yao-yao, and WANG Shu-tao
As an important fossil energy source, oil is an indispensable part of human society’s production activities. When the oil is mined and used, it could be leaked inevitably. The leaked oil will pollute the ecological environment. Therefore, it is necessary to deal with oil spills in a timely manner. Accurate identificatiAs an important fossil energy source, oil is an indispensable part of human society’s production activities. When the oil is mined and used, it could be leaked inevitably. The leaked oil will pollute the ecological environment. Therefore, it is necessary to deal with oil spills in a timely manner. Accurate identification of petroleum species is a prerequisite for handling oil spills. Petroleum contains a variety of substances with fluorescent properties. Therefore, fluorescence spectroscopy is an effective method for detecting petroleum. Due to a large number of components in the oil, the spectral information overlaps seriously, and the identification is difficult. The third-order calibration method has the “third-order advantage”. It can distinguish the data under high collinearity and high noise level. Alternating weighted residue constraint quadrilinear decomposition (AWRCQLD) algorithm is a third-order correction method. AWRCQLD algorithm has the advantages of faster convergence speed and insensitivity to component numbers. Therefore, in this paper, the three-dimensional (3D) fluorescence spectroscopy combined with AWRCQLD algorithm is used to detect the mixed oil. First, sodium dodecyl sulfate (SDS) was prepared as a solvent under three salinity conditions. Under each salinity condition, jet fuel and lube were mixed according to different concentration ratios. Thus, 24 calibration samples and 9 prediction samples are obtained. Secondly, using FLS920 fluorescence spectrometer to acquire spectral data of the experimental samples. Then, the effect of scattering was removed by using blank subtraction, and the number of components in the mixed oil is estimated by the core consistent diagnosis method. Finally, using the AWRCQLD algorithm to analysis the four-dimensional spectral matrix. The results show that, in the range of 0~20 salinity, the fluorescence intensity of jet fuel decreases first and then increases, but the fluorescence intensity of lube increases first and then decreases. The analytical spectral curves of the mixed oils are in good agreement with the actual spectral curves of the jet fuel and lube. The recovery rate of jet fuel obtained by AWRCQLD algorithm is 100.2%~109% and the root mean square error is 0.002 1 mg·mL-1; the recovery rate of lube is 91.8%~109.3% and the root mean square error is 0.004 8 mg·mL-1. By introducing the salinity of seawater as a new dimension of data, the three-dimensional spectral data array is superimposed on this dimension to obtain the four-dimensional spectral data array. In this paper, the four-dimensional spectral data matrix is analyzed by the AWRCQLD algorithm. The purpose of qualitative and quantitative analysis of mixed oil under different salinity conditions is achieved. At the same time, this paper provides a reference for detecting petroleum mixed oil under different salinity conditions..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1769 (2020)
A Benzothiazole-Based Long-Wavelength Fluorescent Probe for Dual-Response to Viscosity and H2O2
ZHU Dan-dan, QU Peng, SUN Chuang, YANG Yuan, LIU Dao-sheng, SHEN Qi, and HAO Yuan-qiang
Hydrogen peroxide (H2O2) is an important biological molecule and plays vital roles in cell growth, immune responses, and cell signaling pathways. Cellular viscosity is a significant physiological parameter and also indicates the normal or abnormal functions of cells. Moreover, both abnormal levels of H2O2 and cellular Hydrogen peroxide (H2O2) is an important biological molecule and plays vital roles in cell growth, immune responses, and cell signaling pathways. Cellular viscosity is a significant physiological parameter and also indicates the normal or abnormal functions of cells. Moreover, both abnormal levels of H2O2 and cellular viscosity are found to be highly related to some major diseases, such as Alzheimer’s disease and cancers. Therefore, the development of effective analytical tools for simultaneously detecting H2O2 and cellular viscosity is of great significance to elucidating some critical physiological and pathological mechanisms, as well as the diagnosis of some relevant diseases. In this work, we developed a dual-responsive fluorescent probe (1) for viscosity and H2O2. Probe (1) is almost non-fluorescent due to the quenching effect arisen from the twisted intramolecular charge transfer (TICT) process within the probe. While the probe exhibited strong near-infrared fluorescence (~680 nm) in solution with high viscosities, which can be attributed the restricted TICT process. The turn-on fluorescence reached 85 folds with the solution viscosity increased from 1.996 cp to 851.8 cp. Furthermore, probe (1) also can sensitively response to H2O2 with the evolution of a new emission band at about 590 nm. H2O2 can effectively react with the phenylboronic acid moiety of probe (1) and result in the conversion of pyridinium unit to pyridine, which could attenuate the ICT (intramolecular charge transfer) and TICT effects of the probe, and thus lead to a dramatic increase in the fluorescence intensity as well as a blue-shift in absorption profile (from 540 to 460 nm) with the observed color of the solution changed from purple-red to yellow. Fluorescence measurements indicated that probe (1) is highly sensitive and selective for H2O2. The fluorescence intensity of the probe assay at 590 nm was found to vary linearly with the concentration of H2O2 in the range of 0～25 μmol·L-1, the detection limit was calculated to be 0.34 μmol·L-1 (3σ). Furthermore, cellular imaging experiment confirmed that probe (1) is highly biocompatible and cell-membrane permeable, and can be utilized for monitoring H2O2 in living cells..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1775 (2020)
Quantum Chemical Calculation of Terahertz Vibration Mode of Glycyrrhizic Acid
YAN Fang, LIU Cheng-hao, WANG Zhi-chun, and LI Wei
Traditional identification method and modern identification method are the main methods in the field of Chinese herbal medicine detection. Although the traditional identification method is widely used in research because of its advantages such as simplicity and low cost, the accuracy of identification depends to some eTraditional identification method and modern identification method are the main methods in the field of Chinese herbal medicine detection. Although the traditional identification method is widely used in research because of its advantages such as simplicity and low cost, the accuracy of identification depends to some extent on whether the operator has rich knowledge and experience in medicinal materials. With the development of spectral analysis technology, modern identification methods based on spectral analysis technology have gradually entered people’s field of vision. Theoretical and a large number of experimental studies have shown that the intramolecular vibration mode of the Chinese herbal metabolites and the low-frequency vibration of the lattice occur in the terahertz band, which can be used to identify the components contained in the Chinese herbal medicine. Glycyrrhizic acid is the main component in licorice. Glycyrrhizic acid was selected as the research object. The terahertz absorption spectrum of glycyrrhizic acid was simulated by a quantum chemical calculation method. The terahertz absorption characteristic of glycyrrhizic acid matched the molecular vibration mode. This work is deeply understood. The interaction of various groups within the glycyrrhizic acid molecule and the formation mechanism of the spectrum are necessary. In order to ensure the reliability of the simulation results, it is necessary to establish the initial configuration of the glycyrrhizic acid molecule, select the appropriate calculation method for structural optimization and frequency calculation, and finally obtain the terahertz absorption spectrum data of glycyrrhizic acid. Through the Gaussian09 semi-empirical theory PM3 algorithm, the characteristic absorption peaks of the glycyrrhizic acid terahertz are located at 0.87, 1.17, 1.56 and 2.76 THz, respectively. The characteristic peak at 1.56 THz is exactly the same as the experimental results in the reference literature, verifying the reliability of the calculation results. Since each glycyrrhizic acid molecule contains 120 atoms, the system is so large that it cannot exhibit its complete structure when it is analyzed by vibration mode. Therefore, the planar structure of glycyrrhizic acid molecules is used instead of the three-dimensional structure to carry out the vibration of the terahertz characteristic absorption peak. Turn analysis. The analysis shows that the terahertz characteristic absorption peak of glycyrrhizic acid molecule is related to the oxygen-containing functional group and the ring-like vibration of the carbon ring, but is mainly formed by twisting of the oxygen-containing functional group in the glycyrrhizic acid molecule..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1780 (2020)
Identification of Vitamin B Using a Quad-Peak Terahertz Metamaterials Sensor
WANG Yue-e, LI Dong-xia, LI Zhi, and HU Fang-rong
Water-soluble B vitamins are necessary nutrients to maintain the normal physiological function of the human body. Ingestion of proper amount is beneficial to growth, metabolism and development, but excessive intake is seriously harmful to the body. Therefore, the research of vitamin detection methods has attracted the Water-soluble B vitamins are necessary nutrients to maintain the normal physiological function of the human body. Ingestion of proper amount is beneficial to growth, metabolism and development, but excessive intake is seriously harmful to the body. Therefore, the research of vitamin detection methods has attracted the attention of quality control departments and scholars at home and abroad. Traditional microbial, chemical and high performance liquid chromatography (HPLC) methods for vitamin determination have some problems, such as complicated operation, complex sample processing, high cost and so on. It is urgent to develop a B-vitamin detection technology that is simple, fast, and accurate. Special characteristics of terahertz wave make it widely used in the detection of materials. The singular electromagnetic properties of metamaterials and the sensitivity to surface media promote the development and application of terahertz metamaterials in the field of detection. We present an identification method of water-soluble Vitamins B using quad-peak terahertz metamaterials. The sensor consists of an outside aluminum hexagon ring and an inner aluminum circle on high resistance silicon substrate, and are asymmetrically split at the same position deviating from the center of the unit cell. Firstly, the formation mechanism of four peaks and the sensing performance are revealed by using the finite-difference time-domain (FDTD) method, and the frequencies of the four peaks are 0.46, 0.57, 0.66 and 0.90 THz, respectively. During the experiment, the different types of vitamin B (B1, B3, B5 and B6) aqueous solution were dripped on the surface of the metamaterial sensor with the same concentration (0.5 mg·μL-1). The transmission spectra were measured by the THz time domain spectroscopy (TDS) system, and the frequency offsets of four resonance peaks were obtained. The simulation and experimental results show that the sensitivity of the sensor formed by the coupling of inner and outer rings are significantly higher than that of the sensor formed by the oscillation of the electric dipoles of the single outer or inner ring. The four peaks of the sensor can be used for sensing detection, and the sensing sensitivity of the resonance peaks formed by the coupling of inner and outer rings is relatively higher. The asymmetric double-open rings have excellent sensing properties and can be used for sample sensing in biomedicine and other fields..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1785 (2020)
Detection of Trichlorfon in Soil Using THz-FDS
WANG Yun, QIN Jian-yuan, JIA Sheng-yao, WANG Yan-jie, and WU Xia
With the rapid development of modern agriculture, the use of pesticides has been increasing in both kind and level, and the corresponding problems of pesticide residue have attracted wide attention. Trichlorfon is an organophosphate insecticide used to control a variety of pests and parasites in livestock in the agricuWith the rapid development of modern agriculture, the use of pesticides has been increasing in both kind and level, and the corresponding problems of pesticide residue have attracted wide attention. Trichlorfon is an organophosphate insecticide used to control a variety of pests and parasites in livestock in the agriculture. Excessive intake of trichlorfon in the human body can cause problems in immune function, and even life-threatening. Therefore, the detection of trichlorfon residues is very important. Due to the unique properties of perspectivity, safety and spectroscopic fingerprinting ability, THz waves have achieved significant advances and applications as a new detection technology, and have beenin the fields of defense, industry, semiconductor, communication, biological medicine, pharmaceutical, agroproducts, food etc. Compared with traditional pesticide detection methods, terahertz spectroscopy has the characteristics of easy operation, short time-consuming, low cost and non-destructive. In this paper, terahertz frequency domain spectroscopy (THz-FDS) is used to detect trichlorfon in soil. The spectrum of pure trilobite tablets was analyzed. It was found that trichlorfon had characteristic absorption peaks at 1.18, 1.55 and 1.91 THz. DFT model B3LYP and basis function 6-31G(d) were used to calculate the single isolated molecule of trichlorfon to explain the source of these absorption peaks and verify the accuracy of the experimental results. In addition, 24 spectra of different contents (0.5%, 1%, 5%, 10%, 20%, 30%, 40%, and 50%) of trichlorfon in the soil were collected. It was found that the absorbance increased with the increase of the content when the content is more than 5%, showing a good linear relationship. The 24 spectra were divided into a calibration set and a prediction with a ratio of 3∶1, and were modeled by partial least squares method. The model has a relatively high correlation coefficient (>0.993 04), lower corrected root means square error (<0.021 9), a predicted root mean square error (<0.024 6), and a cross-validation root mean square error (<0.028 6). This paper provides a new method for the qualitative and quantitative analysis of pesticide residues in soil, as well as a new idea for the detection of pollutants in soil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1791 (2020)
Studies on Plasticized Cellulose Diacetate with Ionic Liquid by Fourier Transform Infrared Spectroscopy (FTIR) and Two-Dimensional Correlation Spectroscopy
LIU Na, YUAN Wei, and WANG Hua-ping
In this study, the interaction between cellulose diacetate (CDA)and ionic liquid(IL) was studied at room temperature (25 ℃) and in the temperature range from 35 to 210 ℃ with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) as plasticizer, using Fourier transform infrared spectroscopy (FTIR) and two-dimensionaIn this study, the interaction between cellulose diacetate (CDA)and ionic liquid(IL) was studied at room temperature (25 ℃) and in the temperature range from 35 to 210 ℃ with 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) as plasticizer, using Fourier transform infrared spectroscopy (FTIR) and two-dimensional correlation spectroscopy analyzer, guiding for melt process of plasticized CDA in theory. The results showed that at 25 ℃ changes occurred in the positions or intensity of absorption bands assigned to hydroxyl forming hydrogen bonds, acetyl groups in CDA, the anion in BMIMPF6 and C-H in imidazole ring in plasticized CDA compared with CDA, in which absorption peaks’positions would shift or their intensity would become weaker, and the changes depended on the content of BMIMPF6 in CDA. It has proved that there were interactions between BMIMPF6 and CDA, and the interactions were formed between C-H in imidazole ring of BMIMPF6 and acetyl group in CDA, C-H in imidazole ring and C-O in the backbone of CDA, the anion of BMIMPF6 and acetyl group in CDA, which helped destroy and weaken the original hydrogen bonds network structure in CDA. In un-plasticized CDA, the absorption peaks of OH group forming intramolecular hydrogen bonds existing in the whole heating process from 35 to 210 ℃ became gradually weaker and shifted towards the shorter wavelength side with the rise of temperature, and acetyl group absorption bands remained almost unchanged. However the changes of absorption peaks assigned to OH group in plasticized CDA had been accelerated, and the OH group absorption peaks vanished completely at a temperature above 180 ℃. Besides, the absorption bands assigned to CO and C-O in acetyl group and C-O in the backbone of CDA had shifted and decreased in the intensity in plasticized CDA. It can be concluded that the thermal stability of CDA was reduced by BMIMPF6. Then a further investigation into plasticized CDA was carried on in the temperature range from 35 to 170 ℃ by two-dimensional correlation spectroscopy, and the sequential order of the responses from different chemical groups in plasticized CDA towards the variation of temperature was illuminated. The results showed that the dominating changes of interactions in plasticized CDA during heating would start with the interaction between C-H in imidazole ring of BMIMPF6 and CO in acetyl group in CDA, then remove the interaction between anions and cations in BMIMPF6. Subsequently isolated CO, C-O and methyl groups were released fromassociated acetyl groups originally forming H-bonds as H-bonds were broken by heating, and then interacted with anions and cations in BMIMPF6 respectively, which was followed by the interactions between C-O in the backbone of CDA and BMIMPF6. The interaction between CDA and BMIMPF6 was stronger than original H-bonds interactions in CDA and interactions between anions and cations in BMIMPF6, and would be reinforced with the rise of temperature..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1796 (2020)
A New NIR Calibration Transfer Method Based on Parameter Correction
HU Yun, LI Bo-yan, ZHANG Jin, and PENG Qian-rong
Model transfer plays an important role in solving the problem of the difference between near infrared (NIR) spectroscopic instruments and the prediction difficulty of models. The spectral differences between the same samples taken on different NIR instruments were identified using the principal component-Mahalanobis diModel transfer plays an important role in solving the problem of the difference between near infrared (NIR) spectroscopic instruments and the prediction difficulty of models. The spectral differences between the same samples taken on different NIR instruments were identified using the principal component-Mahalanobis distance method. Based on the constrain conditions of Tikhonov regularization (TR) and model parameter correction, a new algorithm (called new Tikhonov regularization-based calibration transfer, NTRCT) was proposed for calibration transfer between NIR instruments, so as to facilitate the share and use of the calibration models. The spectra of a set of standard samples were first utilized to establish a specific function that could minimize the prediction errors obtained from the master and slave instrumental models. By constraining the difference of the model parameters, the parameters of the slave instrument model were then determined, to achieve the purpose of model transfer from the master instrument to the slave one. This method was applied to analyze the content of the active pharmaceutical ingredient (API) of tablets and quantify the contents of total alkaloids and total sugars in tobacco leaves respectively, by means of their NIR spectra acquired on different instruments. The results showed that the root means square error of prediction (RMSEP) of samples taken on the salve instrument was reduced from 8.3 mg, 0.49% and 1.91% to 3.9 mg, 0.09% and 0.83% respectively; when 15 standard samples were employed for modelling. As the calibration transferred all the resulting RPD values were larger than 3.0, and the sample predictions from the salve instrumental spectra were thus significantly improved. The method was explicit and intuitive in theory, and had good accuracy in sample prediction in practical applications. It provided a new idea for calibration transfer method with standard samples..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1804 (2020)
Transmission Surface Enhanced Infrared Spectroscopy Based on AgNPs-Cu Foam Substrate for the Detection of Thiram Pesticides
JIANG Xin-cheng, SHI Lin-hong, LUO Bin, WANG Dong-mei, WANG Zhao-li, FAN Mei-kun, and GONG Zheng-jun
Surface enhanced infrared absorption spectroscopy is a promising analytical technique and has been widely used in many fields recently. The key to the SEIRAS spectroscopy lies in the preparation of substrate with infrared enhancement effect. However, the cost, process steps and consuming time of the SEIRAS substrate prSurface enhanced infrared absorption spectroscopy is a promising analytical technique and has been widely used in many fields recently. The key to the SEIRAS spectroscopy lies in the preparation of substrate with infrared enhancement effect. However, the cost, process steps and consuming time of the SEIRAS substrate preparation method have yet to be optimized. Metal materials are usually difficult to be used as support materials for transmission SEIRAS (T-SEIRAS)substrates due to its opacity. In this study, we innovatively used copper foam materials with a three-dimensional pore structure as support materials and loaded silver nanoparticles on copper foam based on improved displacement reaction principle. A fast, simple and low-cost method for preparing T-SEIRAS substrate was developed in this research. The dosage of surfactant and reaction time were optimized. The results showed that when the dosage of silver nitrate (0.2 mmol·L-1) was 10 mL, the dosage of Polyvinylpyrrolidone (PVP) (0.05 g·mL-1) was 2 mL and the reaction time was 30 s, the infrared enhancement effect of the substrate was optimum. The characterization of SEIRAS substrate by scanning electron microscopy (SEM) and X ray photoelectron spectroscopy (XPS) showed that silver nanoparticles, from tens to one hundred nanometer, were successfully loaded on the Cu foam. The optimized AgNPs-Cu foam SEIRAS transmission substrate could significantly enhance the infrared signal of the probe molecule 11-mercaptoundecanoic acid (MUA) and the thiram pesticide. Its enhancement multiple of MUA at 1 689 cm-1 is 32.7 times, and 2.9 times of thiram at 1 371 cm-1. Linear fitting of absorption signal intensity at 1 236, 1 371, 1 495 cm-1 and the concentration of thiram was investigated. Linear optimum was found at 1 236 cm-1 with a correlation coefficient of 0.923. The detection limit of thiram was 0.024 mg·mL-1. The experimental results of this study provide a new scheme for the rapid and simple preparation of SEIRAS transmission substrate and a new idea for the rapid on-site detection of thiram pesticide..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1809 (2020)
Spectroscopic Study of Green-Yellow and Green Turquoise Associated Minerals from Zhushan, Hubei Province
KU Ya-lun, YANG Ming-xing, and LI Yan
Recently, there have been many natural minerals commonly known as “turquoise associated minerals”, which are rich in color, such as purple, white, brown, yellow-green, green and so on. However, green-yellow and green turquoise associated minerals have a more similar appearance to other color turquoise associated mineraRecently, there have been many natural minerals commonly known as “turquoise associated minerals”, which are rich in color, such as purple, white, brown, yellow-green, green and so on. However, green-yellow and green turquoise associated minerals have a more similar appearance to other color turquoise associated minerals and are more difficult to identify. In this study, to explore their different features, two green-yellow and green turquoise associated minerals samples (sample E and sample F) were selected from Zhushan County market of Hubei Province. These minerals have been used for the basic gemological test, electron microprobe micro, X-ray powder diffractometer, micro-laser Raman spectrometer as well as Ultraviolet-Visible spectrometer. The test results show that the main mineral components of the associated ores are fluorapatite, muscovite and so on. The results of electron microprobe backscattering photographs show that the associated mineral samples are polyphase mixtures of tiny crystalline particles. And quantitative analysis of the chemical composition of the two phases shows that the dark phase is an aluminium-containing silicate, while the light phase is calcium-containing phosphate. In addition, the samples also contained CuO (2.27%~6.22%) and FeO (2.43%~4.99%), whereas the contents of CuO and FeO in sample F are higher than those in sample E. Furthermore. Damaging test of X-ray powder diffraction can accurately test the main minerals of the samples which are fluorapatite, muscovite and a small amount of turquoise. The typical Raman spectra of fluorapatite near 964 cm-1 and muscovite near 203, 432, 709 and 3 626 cm-1 can be effectively identified from turquoise. The results of ultraviolet-visible absorption spectroscopy show that the color origin of the samples is similar to that of turquoise, mainly due to the electron transition of Cu2+ and Fe3+ ions. Based on the relatively systematic spectroscopic testing of the samples, the authors suggest that Raman spectroscopy is a nondestructive, rapid and effective method for identifying different mineral phases in turquoise associated minerals. The typical Raman peaks of fluorapatite and Muscovite can effectively distinguish them from turquoise..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1815 (2020)
Spectroscopic and Cytotoxicity Study on the Influence of (-)-Epigallocatechin-3-Gallate on the Interaction of Daunorubicin with Human Serum Albumin
GUO Qing-ying, LIU Min, ZHAO Yan-na, WU Yu-shu, SUN Bin, LIU Jie, and HAN Jun
Tea polyphenols play roles in the augmentation of antitumor effects, the reversal of multidrug resistance, and the reduction of side effects of antitumor drugs. Tea polyphenols could be used as biochemical modulators in cancer therapy. In this study, the interaction of daunorubicin (DNR) with human serum albumin (HSA) Tea polyphenols play roles in the augmentation of antitumor effects, the reversal of multidrug resistance, and the reduction of side effects of antitumor drugs. Tea polyphenols could be used as biochemical modulators in cancer therapy. In this study, the interaction of daunorubicin (DNR) with human serum albumin (HSA) and the effect of epigallocatechin gallate (EGCG) on the binding process under physiological condition were studied by fluorescence spectroscopy, UV-Vis absorption spectroscopy, circular dichroism (CD) spectroscopy, and dynamic light scattering (DLS). The cytotoxicity of DNR single drug, EGCG+DNR combined drug, and their complexes with HSA against human cervical cancer HeLa cell line was determined by MTT assay. Fluorescence quenching result and difference spectra of UV-Vis absorption revealed the formation of a static complex between DNR and HSA. Quenching constants, binding constants, the numbers of binding sites, enthalpy and entropy changes were obtained from fluorescence data. Positive enthalpy and entropy changes indicated that the binding of DNR to HSA was mainly driven by entropy. The hydrophobic interaction was the main driving force. Site marker competitive experiments combined with synchronous fluorescence spectra showed that DNR mainly bound to subdomain IIA of HSA and was closer to tryptophan residues. In HSA+EGCG+DNR ternary system, the fluorescence data processing model of the ternary system was established. The number of binding sites and binding constants for DNR-HSA interaction in the presence of EGCG obtained by Matlab fitting were obviously decreased in the presence of EGCG. This indicated that the presence of EGCG might decrease the binding affinities of DNR to HSA. In addition, in the presence of EGCG, the binding constant of DNR to HSA increased with the elevation of temperature. This implied that the main driving force for the binding process was still the hydrophobic interactions. CD spectroscopy and DLS studies showed that drug-protein binding could affect the conformation and particle size of the protein, resulting in a decrease in the α-helical content of HSA and an increase in particle size. The α-helical content in (HSA+EGCG)+DNR ternary system was greater than that in the corresponding HSA+DNR binary system, while the hydraulic diameter of the ternary system was smaller than that of the binary system. This indicated the presence of EGCG weakened the binding of DNR to HSA due to the competitive binding between EGCG and DNR. This conclusion was consistent with the fluorescence experiment result of the ternary system. Furthermore, the cytotoxicity of DNR and HSA+DNR complex in the presence or absence of EGCG was discussed, and the results indicated that the combination of DNR with EGCG had the synergistic effect and HSA can enhance the cytotoxicity of DNR. Obtained results would provide beneficial information on the combination of EGCG and DNR in the clinic. This study showed that the spectroscopic method could provide strong support for the study of the interaction between combined drugs and proteins..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1821 (2020)
A General Model for the Peroxidation Values of Two Vegetable Oils Based on Near Infrared Spectroscopy
PENG Dan, LI Lin-qing, LIU Ya-li, BI Yan-lan, and YANG Guo-long
The rapid and accurate detection of peroxide value is of great significance to the quality of edible oils and food safety control. Near-infrared (NIR) spectroscopy is an ideal method for measuring peroxide values, but the establishment of calibration models requires a lot of resources. In this paper, based on the relatThe rapid and accurate detection of peroxide value is of great significance to the quality of edible oils and food safety control. Near-infrared (NIR) spectroscopy is an ideal method for measuring peroxide values, but the establishment of calibration models requires a lot of resources. In this paper, based on the relationship between near-infrared spectroscopy and lipid peroxide value, the feasibility of establishing a general calibration model for measuring peroxide value in different types and levels of vegetable oils was studied. First, different grades of soybean oil and rapeseed oil were studied. The near-infrared spectra of the two vegetable oils were analyzed by two-dimensional correlation spectroscopy, and the optimal detection band of the general model for peroxide value was selected by interval least squares method (iPLS). Then, the effects of orthogonal signal correction (OSC), standard normal variable transformation (SNV) and second derivative (SD) on the prediction precision of general models were investigated. Further, the prediction performances of three modeling methods, including principal component regression (PCR), partial least squares (PLS) and support vector machine regression (SVR), were compared in detail. At last, four general prediction models for soybean oil (including first-grade and third-grade), rapeseed oil (including first-grade, third-grade and fourth-grade), first-grade vegetable oils (including soybean oil and rapeseed oil) and third-grade vegetable oil (including soybean oil and rapeseed oil) were constructed. The experimental results showed that the change of peroxide value of vegetable oil could be detected by NIR spectroscopy technology, and its spectral changes mainly resided in the region from 1 700 to 2 200 nm. The optimal band, preprocessing method and modeling method of the general model were 1 700~2 200 nm, SD method and PLS method, respectively. Among the four general models, the one for the first-grade vegetable oils (including soybean oil and rapeseed oil) can get better performance. The root means square error of prediction (RMSEP) and the square correlation coefficient (R2) are 0.412 and 0.920, respectively. Compared with the models of first-grade soybean oil or rapeseed oil, the prediction results are roughly the same. It meant that it was feasible to establish a general model with high accuracy between vegetable oils with similar production processes for reducing the workload of repetitive modeling. In addition, in order to expand the versatility of the general model, it was necessary to continuously update the model with new kinds of vegetable oils..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1828 (2020)
Density Functional Theory Study on Surface-Enhanced Raman Spectral of Amaranth
LU Mei-hong, JIA Juan, LEI Hai-ying, WANG Zhi-jun, ZHANG Zhu-li, CHEN Xu-li, and WU Yan-bo
Amaranth is a synthetic food additive. It is often added to soda, hawthorn and candy, etc. However, Amaranth is made from the coal tar isolated by the benzene dye as raw material, and excessive consumption will lead to genetic mutations and even cancer, which is harmful to health. Therefore, the detection of Amaranth iAmaranth is a synthetic food additive. It is often added to soda, hawthorn and candy, etc. However, Amaranth is made from the coal tar isolated by the benzene dye as raw material, and excessive consumption will lead to genetic mutations and even cancer, which is harmful to health. Therefore, the detection of Amaranth is important and necessary. Surface-enhanced Raman spectroscopy has the advantages of simple pre-processing, rapid analysis and high accuracy for samples, which has been increasingly shown great potential in the fields of chemistry, biology and medicine. At present, the theoretical and experimental research on Amaranth with Raman spectroscopy technology has not been reported. The study of Raman spectroscopy and the theoretical mechanism of surface enhancement can provide a reliable scientific basis for the detection and identification of Amaranth in food. Therefore, the study on the surface-enhanced Raman mechanism of Amaranth and compare it with the experimental results using the density functional theory is necessary. It has a good prediction and guiding significance for the detection of Amaranth in food. On the one hand, Amaranth was detected by using micro-confocal Raman spectrometer. On the other hand, the structure of Amaranth was built, and Density Functional Theory was used to optimize the molecular structure and calculate the front-line orbit, electrostatic potential, polarization and natural bond orbital analysis. And the azo group (-N15N16-) is the best position for Amaranth to coordinate with Ag atom. The optimum structure and surface-enhanced Raman spectra of Amaranth-Ag1, Amaranth-Ag3 complexes molecules were calculated by using B3LYP function with 6-31++G (d, p) (C, H, O, N, S, Na) base set and Sdd (Ag) base set, receptively. The results showed that the experimental results at 1 228, 1 329, 1 467 and 1 529 cm-1 were in good agreement with the theoretical results and the Raman activity of Amaranth molecule was obvious. Raman enhancement effect of Amaranth-Ag complex was significant and the Raman enhancement effect increases with the number of Ag atoms. It can be found that not only the numbers of Raman peaks increased, but also the corresponding intensity increased. Furthermore, the vibrational mode was assigned and the characteristic peaks for detection and inspection of Amaranth can be found. The study provides an experimental reference and theoretical basis for the detection of Amaranth by using surface-enhanced Raman spectroscopy..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1833 (2020)
Effects of Prediction Model of Kolar Pear Based on NIR Diffuse Transmission under Different Moving Speed on Online
CHEN Dong-jie, JIANG Pei-hong, GUO Feng-jun, ZHANG Yu-hua, and ZHANG Chang-feng
With the aim of solving problems related to cost, and the complicated structure of the online grading and inspection system for detecting the quality of pears, the online non-destructive system was designed for inspecting and classification of the internal quality of pears. Based on the system, the effects of predictioWith the aim of solving problems related to cost, and the complicated structure of the online grading and inspection system for detecting the quality of pears, the online non-destructive system was designed for inspecting and classification of the internal quality of pears. Based on the system, the effects of prediction models on the Soluble Solids Content (SSC) and firmness of pears were researched under the different moving speeds (0.3 and 0.5 m·s-1) . Collected spectra from the same position of the pear were discrepancy at different moving speeds. Due to the discrepancy in the collected spectra, adapting spectral pre-processing methods, as SG-smoothing, SG-convolution derivative, multiple scattering correction (MSC), standard normal energy transformation (SNV), Normalization, was to eliminate differences. Adopt Partial Least Squares (PLS), prediction models of SSC and hardness for Korla Pears were established at moving speeds of 0.3 m·s-1 (S1) and 0.5 m·s-1 (S2). The results showed that the established SSC prediction model at 0.5 m·s-1 was more effective than 0.3 m·s-1 by using SG-DER (Savitzky-Golay Derivative) processing spectrogram. The correlation coefficient of the prediction set, and the root mean square errors of prediction were to be 0.880 2 and 0.391 5°Brix respectively. However, when the moving speed was 0.3 m·s-1, established the SSC model, by adapting SGS (Savitzky-Golay Smooth) processing spectrogram, was more robust than at 0.5 m·s-1. Its correlation coefficient of the prediction set, and the root mean square errors of prediction were to be 0.820 2 and 0.470 8 N respectively . Afterwards two speed hybrid prediction models were established. Competitive adaptive re-weighted sampling (CARS) and Successive projections algorithm (SPA) were used to select the characteristic variables, and PLS was used to establish hardness and SSC prediction models at mixed speeds. In view of the perspective of the model effect, SPA and CARS effectively reduced the number of variables, improving the online prediction ability and processing data speed, and enhancing the robustness of the model. Using CARS to select 24 variables from a total of 501, then which established the CARS-PLS model. Establishing the SSC prediction model was more efficient, and its correlation coefficient of the prediction set and root mean square errors of prediction were calculated as 0.915 0 and 0.371 9°Brix respectively. Using SPA to select, 32 variables were selected from a set of 501, and a firmness model was established. The correlation coefficient of the prediction set and the root mean square errors of prediction were ascertained as 0.821 0 and 0.492 0 N respectively. Establishing predictive quality model at the mixing speed is more robust than at the single speed. The research showed that the different moving speeds have different effects on the fruit quality prediction models. The research provides technical support for on-line classification of fruit quality.<英文关键词Near-infrared spectroscopy;Korla pear;Different movement speeds;On-line inspection.
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1839 (2020)
Study on Refractive Index Characteristics of Chitosan Hydrogel
ZHANG Rong-zhen, WANG Zhi-bin, LI Ke-wu, and CHEN You-hua
Hydrogel is a new functional polymer material with a three-dimensional network structure. Hydrogels are widely used in drug release control, adsorption materials, biomimetic engineering, fiber optic sensing, tissue engineering, smart wear and other aspects, due to its injectability, good histocompatibility, non-toxic sHydrogel is a new functional polymer material with a three-dimensional network structure. Hydrogels are widely used in drug release control, adsorption materials, biomimetic engineering, fiber optic sensing, tissue engineering, smart wear and other aspects, due to its injectability, good histocompatibility, non-toxic side effects, biodegradability in vivo, and environmental sensitivity. The sensing of the hydrogel is mainly caused by the change of external environment factors, causing the difference of swelling degree, which causes the water molecules to fill the inner pores of the gel to different extents, showing the process of the change of the overall refractive index of the hydrogel. In order to study the effect of different swelling degree on refraction index of the hydrogel, in this paper, chitosan was used as raw material, ammonium persulfate, N and N-methylenediacrylamide were used as an initiator and crosslinking agent respectively, and grafted with acrylic acid, and chitosan hydrogel was prepared chemically in a nitrogen environment. By designing the measurement structure and building the experimental platform, the swelling properties of chitosan hydrogel were tested, and the swelling degree of the gel was calibrated; the transmission spectrum of chitosan hydrogel was detected by spectrograph with halogen lamp as the light source; using the principle of light propagation on the surface of the medium and the principle of the polarization of light waves, the transmission spectrum of chitosan hydrogel is analyzed; the variation of the refractive index of chitosan hydrogel under different swelling degrees was studied, and it was found that the refractive power of gels with different wavelengths was different under different swelling degrees; through data processing, the range of gel refractive index change with the swelling degree and the sensitivity Q1 were calculated when the wavelength was 400 nm. By fitting the experimental data, the response law of refraction index of chitosan hydrogel to swelling degree and wavelength was obtained, and the fitting degree was higher, and it provides the experimental basis for the application of chitosan hydrogel in optical sensing. Through experiments, it is demonstrated that chitosan hydrogel has excellent swelling properties, wide range of refractive index variation and high sensitivity, it has certain advantages in intelligent wear, skin simulation, optical sensing and other fields..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1846 (2020)
A Quick and Simple Method for Extracting Unsaponifiables of Vegetable Oil
HUANG Rui, LI Yu, HE Wen-xuan, LU Xiao-yong, CHEN Wei-jian, CHEN Ting, and ZHANG Yan-jie
Infrared spectroscopy combined with chemometrics, has become a popular method for the identification of vegetable oil. However, this combination is currently based on the infrared spectra of vegetable oil. Although the infrared spectra information of the saponifiable of vegetable oil is extracted, the information of unInfrared spectroscopy combined with chemometrics, has become a popular method for the identification of vegetable oil. However, this combination is currently based on the infrared spectra of vegetable oil. Although the infrared spectra information of the saponifiable of vegetable oil is extracted, the information of unsaponifiable is not effectively extracted. The sensitivity of the constructed vegetable oil identification model still needs to be improved. Unsaponifiable is important characteristic components. In order to effectively obtain their infrared spectra, it is necessary to separate and concentrate it in advance. However, the existing separation and enrichment method is cumbersome and time-consuming, and can’t be adopted for the batch samples of vegetable oil. In this paper, under high alkalinity, instead of reflux heating ultrasonic heating, was used to shorten the saponification time. On this basis, through ① the reasonable ratio of n-hexane, ethanol and water to form an easy layering system; ② one extraction replacing multiple extractions; ③ designing and developing a dedicated solid phase extraction small column to rapid remove residual alkaline substance and water in the organic phase at one time, the extraction time of unsaponifiable was shortened greatly. The time of separation and enrichment was shortened from about 2~3 hours with the national standard method to about 20 minutes with the newly established method. The new method has good stability. The same sample was prepared by different people, and their infrared spectra were the same, which could ensure the same infrared spectra for one sample. The establishment of this method not only solves the key technical problems of constructing a model of vegetable oil identification based on infrared spectra of unsaponifiable combined with chemometrics but also creates a prospect for rapid sample preparation of unsaponifiable by chromatography/hyphenated chromatography. Using the rapid separation and enrichment method to unsaponifiable of five different brands of sesame oil and five different brands corn oil were extracted, and their spectra were collected. The experimental result shows that there is a great difference between infrared spectra of unsaponifiable of sesame oil and that of corn oil, although infrared spectra of sesame oil and corn oil are almost the same. It can be predicted that the infrared spectra of vegetable oils can be combined with their unsaponifiable infrared spectra to greatly improve the sensitivity of identification methods for some kinds of vegetable oil such as sesame oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1852 (2020)
Predicting the Biochemical Methane Potential of Organic Waste with Near-Infrared Reflectance Spectroscopy Based on GA-SVM
YAO Yan, SHEN Xiao-min, QIU Qian, WANG Jing, CAI Jin-hui, ZENG Jiu-sun, and LANG Xiao-yu
Anaerobic fermentation technology is one of the most promising technologies for the utilization of organic waste resources. Its research and utilization have been widely carried out at home and abroad. Usually, biochemical methane potential (BMP) is used to represent the anaerobic degradation of the material in the anaAnaerobic fermentation technology is one of the most promising technologies for the utilization of organic waste resources. Its research and utilization have been widely carried out at home and abroad. Usually, biochemical methane potential (BMP) is used to represent the anaerobic degradation of the material in the anaerobic degradation technology of organic waste. The traditional measuring methods of BMP, are usually expensive and time-consuming. Therefore, near-infrared spectroscopy is proposed to rapid predict the biochemical methane potential (BMP) of organic waste in this paper. And genetic algorithm (GA) combined with support vector machine (SVM) is applied to establish a functional model to predict the biochemical methane potential of organic waste. 64 samples of aquatic plants and algae are collected from the south and east of China. The original BMP data of samples were obtained from the experimental scale digesbers. At the same time, near-infrared spectral data are obtained by Fourier transform near-infrared spectrometer. First of all, the prediction models were developed by the principal component regression, partial least squares, recursive exponential partial least squares (RPLS) on the pre-processed data, respectively. The aim is to connect the original BMP date with the spectral data and realize the rapid prediction of aquatic plants and algae BMP. The results show that the RPLS method on the full spectral can solve the problem of poor robustness and the poor data interference caused by the traditional PLS method. Although this method improves the robustness of the model, it has slow response speed and low computational efficiency. Therefore, we proposed a genetic algorithm (GA) combined with support vector machine (SVM) method, which is suitable for small sample cases, has good global search ability, and also avoids the traditional process from induction to deduction, and eliminates a lot of redundant sample information. In summary, the GA-SVM method is simple, and it has good stability. Combined with the band assignment of the near-infrared spectrum, it could know that the 1 404 characteristic wavelength points were selected, and roughly divided into 3 representative bands by genetic algorithm (GA), so we built the regression model by support vector machines on the selected characteristic bands. According to the results of model evaluation, it is known that the prediction model based on GA-SVM not only simplifies the date scale, but also improves the prediction accuracy. The root mean square error of prediction (RMSEP) is 10.32 mL, the coefficient of determination (R2) is 0.92; the residual prediction deviation (RPD) is 6.56. Compared with the models PLS and RPLS, the RMSEP was decreased by 19.56 and 14.81 mL respectively; the R2 increased by 0.06 and 0.04, the RPD increased by 4.31, 3.85 respectively. The results show that the NIRS model based on GA-SVM can predict the biochemical methane potential of organic waste rapidly and has higher accuracy, it can replace the traditional BMP determination method to meet the needs of rapid detection..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1857 (2020)
Baseline Correction of UV Raman Spectrum Based on Improved Piecewise Linear Fitting
ZHAO Man, GUO Yi-xin, HE Yu-qing, GUO Hong, JIN Wei-qi, and REN Lin-mao
UV Raman spectroscopy has the characteristics of high Raman scattering intensity, easy fluorescence spectrum separation, little influence by environmental interference and safety to the human eye. In this paper, the ultraviolet Raman spectrometer uses a laser with a wavelength of 266 nm. The Raman spectrum and the fluoUV Raman spectroscopy has the characteristics of high Raman scattering intensity, easy fluorescence spectrum separation, little influence by environmental interference and safety to the human eye. In this paper, the ultraviolet Raman spectrometer uses a laser with a wavelength of 266 nm. The Raman spectrum and the fluorescence spectrum will partially overlap, which increases the difficulty of accurately obtaining the characteristic information of the laser Raman spectrum, and further affects the identification and analysis of the sample. Therefore, baseline corrections need to be performed prior to analyzing Raman spectroscopy to eliminate fluorescence interference. According to the distribution characteristics of the mixed spectrum of ultraviolet Raman and fluorescence, the fluorescence spectrum has a gradual increase and is close to a piecewise linear increase. Therefore, fitting a fluorescence spectral baseline using a piecewise linear function is a relatively simple method, so that the troughs of the characteristic peaks just fall on the baseline. Aiming at the problem that the traditional piecewise linear fitting baseline correction method is over-reliant on the operator and the low level of automation, improved UV-Raman spectroscopy piecewise linear fitting baseline correction method is studied. (1) First the spectral data of the original signal after different smoothing iterations is obtained. Since the peak is a high-frequency signal with respect to the baseline, the spectral intensity at the peak position gradually decreases and changes greatly, while that at the baseline portion gradually rises and the relative change is small during the multiple smoothing process. So the standard deviation (SD) of the spectral intensity at the spectral peaks and the baseline points is different after different smoothing iterations. (2) Then the position of the quasi-valid baseline points is determined by comparing the spectral intensity deviations. The quasi-valid baseline points can be extracted by appropriately setting the threshold; (3) Next the quasi-valid baseline points divide the entire Raman spectrum into N characteristic peak intervals. Comparing the lines obtained by connecting the two ends of the characteristic peak interval with the spectral intensity of the characteristic peak interval, if the characteristic peaks are all above the straight line, there is no over-fitting, otherwise the endpoints of the characteristic peaks move toward the peak direction and are connected again by straight lines. The above process is repeated until the characteristic peaks are all above the line connecting the two ends of the interval, and the valid baseline points are obtained. (4) Finally, all adjacent valid baseline points are connected in a straight line by segment to get the baseline of the entire spectrum. The corrected Raman spectrum is obtained by subtracting the baseline from the original spectrum. Baseline calibration experiments of simulated and actual measured UV and fluorescence hybrid spectra show that the method of this paper can automatically determine the position of the baseline point and obtain better baseline correction effect than the traditional method, which will provide more accurate spectral information for the next spectral analysis..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1862 (2020)
Research on Near Infrared Spectral Feature Variable Selection Method Based on Improved Harmonic Search Algorithm
ZHANG Lei, DING Xiang-qian, GONG Hui-li, WU Li-jun, BAI Xiao-li, and LUO Lin
Near-infrared spectroscopy has been widely used in many fields for detection and analysis because of its advantages of simplicity, speed, efficiency, low cost, and environment protection. However, the NIR spectra also contain interferences such as high variable dimension, multiple collinearities, redundant information,Near-infrared spectroscopy has been widely used in many fields for detection and analysis because of its advantages of simplicity, speed, efficiency, low cost, and environment protection. However, the NIR spectra also contain interferences such as high variable dimension, multiple collinearities, redundant information, and high frequency noise. The direct construction of the prediction model not only increases the modeling complexity but also affects the prediction performance and generalization. For this purpose, a spectral feature variable selection method based on the improved Harmony Search algorithm (HS) is proposed. HS is often used to solve feature variable optimization problem. When the spectral variable selection is applied by the HS algorithm, the feature contribution of spectra is firstly calculated by the PLS loading coefficient as the disturbance weight of the improved HS. In the process of optimizing the spectral feature variables, the variable feature contribution is introduced as the excitation factor, and the initial solution vectors are generated by the combination of random traversal and excitation factor. When generating the new harmony vector, the feature contribution is applied as a penalty factor, and the parameters of HS are dynamically adjusted with the number of iterations by adding the balance factor, so as to adapt to the search of spectral variables. It enhances the ergodicity of the search process and the diversity of the population. In order to verify the effectiveness of the algorithm, the NIR PLS models of nicotine, total sugar and total nitrogen using tobacco samples are constructed. After pre-processing the original spectra, this method is used to optimize spectral variables. The prediction performance of each model corresponding to the number of different variables is calculated according to the cumulative frequency at which the variables are selected, and the final selected spectral variables are determined by the increasing trend of the Root Mean Square Error of Calibration (RMSEC) with the variables. The three PLS models are established on the training set and the test set respectively, and they are compared with the full spectrum, Uninformative Variables Elimination (UVE) and Particle Swarm Optimization (PSO). The experimental results show that the coefficient of determination (R2) of nicotine, total sugar and total nitrogen models using the selected variables is 0.921 1, 0.925 7 and 0.941 2, respectively; and the Root Mean Square Error of Prediction (RMSEP) is 0.102 3, 1.034 6 and 0.053 1. Compared with other methods, the RMSEP of this study is low, the R2 of these models is more than 0.92, and the spectral characteristic variables are small. It is shown that the improved HS algorithm can effectively filter the feature spectrum, reduce the modeling complexity, improve the model prediction performance and generalization ability..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1869 (2020)
FTIR and XPS Analysis Comparing the Activation Mechanism of Ca2+ and Fe3+ on Quartz
LIU Rong-xiang, LI Jie, SU Wen-rou, ZHANG Xue-feng, LI Jia-wei, and MENG Liu-yang
During the flotation desilication of iron concentrate, the unavoidable cations (Ca2+, Fe3+) in the pulp have important influences on the floatability of quartz using the anion collecter, and it is of great significance to find out the activation mechanism of the unavoidable cations on the quartz and other pulsar mineraDuring the flotation desilication of iron concentrate, the unavoidable cations (Ca2+, Fe3+) in the pulp have important influences on the floatability of quartz using the anion collecter, and it is of great significance to find out the activation mechanism of the unavoidable cations on the quartz and other pulsar minerals to solve the technical problem of desilication of ultra-pure iron concentrate. At present, there are many pieces of research on the adsorption structure of quartz for collectors, while there are few pieces of research on the adsorption structure and the occurrence mechanism of adsorption strength for inevitable ion-activated quartz. So infrared spectroscopy and XPS analysis were adopted, the spectral characterization of unavoidable ions (Ca2+, Fe3+) activated quartz were performed, and the occurrence forms of oxygen-containing functional groups and unavoidable ions in quartz were analyzed, the mechanism of unavoidable ions activated quartz were also analyzed. The results show that in the infrared characterization, at the appropriate pH value, the addition of Ca2+ and Fe3+ activates the flotation of quartz. When quartz is activated by Ca2+ and Fe3+ and reacts with SDS, the chemical adsorption and physical absorption occur almost at the same time. And the red-shifted wave numbers of Si-O characteristic peak under Fe3+ activation is stronger than that of Ca2+ activation. Ca2+ can activate quartz is due to mono- silicon bond, and the bond action has small bond energy and weak adsorption; Fe3+ activated quartz is due to a dioxy-silicon bond, which has large bond energy and strong adsorption. The XPS test results show that the binding energy of Fe3+ activator activated quartz (Fe(2p) binding energy of 711.16 eV) is stronger than that of Ca2+ activated quartz (Ca(2p) binding energy of 346.93 eV), which makes the chemical displacement of Si(2s) and Si(2p) binding energy larger. It is indicated that the stable Fe-based six-membered ring chelate is formed on the surface of quartz under the activation of Fe3+, and chemical adsorption is more stable and dense, and two active sites are generated; while the unstable Ca-based s chain-like complex is formed on the surface of quartz under the activation of Ca2+, and chemical adsorption is unstable and not so dense. Comprehensive infrared spectrum and XPS analysis show that Fe3+ has stronger activation than Ca2+, and enhance the chemical and physical adsorption between the agent and quartz surface, which is more conducive to the flotation of activation quartz..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1876 (2020)
FTIR Analysis of the Correlations Between Viscous Fluid Flow Characteristics and Molecular Structure of Mixed Oil during Coal-Based Needle Coke Production
CHENG Jun-xia, ZHU Ya-ming, GAO Li-juan, LAI Shi-quan, and ZHAO Xue-fei
During the production of coal-based needle coke, the performance of the mixed oil fluctuates continuously in a coking cycle due to the delayed coking process. How to stabilize the performance of mixed oil is a key factor in ensure the uniformity of needle coke quality. The difference in the properties of mixed oil is mDuring the production of coal-based needle coke, the performance of the mixed oil fluctuates continuously in a coking cycle due to the delayed coking process. How to stabilize the performance of mixed oil is a key factor in ensure the uniformity of needle coke quality. The difference in the properties of mixed oil is mainly reflected in the change of viscosity. In order to quantitatively analysis of the change of mixed oil, the mixed oil with different continuous feeding time in the same production cycle has been detailed analyzed in this study. Briefly, the Fourier Transform Infrared Spectroscopy (FTIR) analyzer and the rotational viscometer have been used as the detection means, and six kinds of molecular structural parameters which calculated from the various range of FTIR spectrum (700～900, 1 550～1 650, 2 800～3 000 and 3 000～3 100 cm-1, respectively) were used as the significant factors to characterized the mixed oil. The correlation between the viscous fluid flow characteristics and the molecular structure of the mixed oil was discussed in detail. The results showed that FTIR spectrum analysis showed that the mixed oil was mainly composed of condensed aromatic rings with partial aliphatic side chains. The branching degree (I1) of aliphatic side chains decreased continuously, and the aromaticity (I2) in aromatic structure increased slightly in the mixed oil during the production of coal-based needle coke. However, the variation of aromatic ring condensation degree I3 and substitution of aromatic rings (I4, I5, I6) changed slightly, which indicated that the degree of condensation of blends changed little with the increase of coking time. The coexistence of multi-component complex aromatic substances in the mixed oil led to easy association among molecules, which made the initial apparent viscosity of the mixed oil was large. And the viscous fluid flow activation energy Eη increased with the prolongation of production time. In theory, the condensation aromatic rings and alkyl side chains have the greatest influence on viscous flow properties, but when I1, I2, I3 and Eη were analyzed, it was found that the goodness of fit of regression curve R2 can only reach 0.71. In fact, the branching degree of the mixed oil was low and the length of the branching chain was short. When the influence of I1 on the viscous flow activation energy was neglected, the goodness of fit R2 of the regression curve obtained by data processing of I2, I3 and Eη decreased. Considered all the molecular structure parameters and Eη for regression analysis, the goodness of fit of regression curve R2 can reach 0.98. The relationship between the viscous fluid flow characteristics and the molecular structure followed the following model: Eη=703.59-55.88I1-7.83I2+5.73I3-1 866.70I4-694.85I5-83.16I6. It can be seen that the viscous flow characteristics were the macroscopic manifestation of all the molecular structure characteristics in the complex system of mixed oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1883 (2020)
Quantitative Analysis of Fuel Blends Based on Raman and Near Infrared Absorption Spectroscopy
LIU Zhe, LUO Ning-ning, SHI Jiu-lin, ZHANG Yu-bao, and HE Xing-dao
Biodiesel is a typical “green energy” with good environmental protection and fuel characteristics. It is usually mixed with diesel to use in diesel engines. However, there is no uniform standard for the blend proportion of diesel and biodiesel at present, and different proportions of diesel/biodiesel blend present diffBiodiesel is a typical “green energy” with good environmental protection and fuel characteristics. It is usually mixed with diesel to use in diesel engines. However, there is no uniform standard for the blend proportion of diesel and biodiesel at present, and different proportions of diesel/biodiesel blend present different combustion performance, which also have a certain impact on diesel engines. In order to measure the concentration of biodiesel in diesel/biodiesel blend quickly and accurately, near infrared spectroscopy (NIR) and Raman spectroscopy have been used in fuel detection. In this paper, the concentration of biodiesel in diesel/biodiesel blends was quantitatively analyzed by using Raman spectroscopy combined with NIR. The Raman spectra and NIRs of diesel/biodiesel blends were measured firstly, and then the spectra were pre-processed by smoothing, baseline correction and normalization. The Raman and NIRs of diesel/biodiesel blend present CO characteristic spectral regions, and show corresponding trends with the increase of biodiesel concentration. The main variation of CO characteristic region with biodiesel concentration in Raman spectra is the characteristic peak at 1 743 cm-1, while the main variation of CO characteristic region with biodiesel concentration in NIRs is the characteristic peak at 4 659 cm-1. Afterwards, the concentration prediction models of biodiesel in mixed fuel based on the strength ratio method and partial least squares (PLS) regression method were established respectively. When using intensity ratio method to establish the biodiesel concentration prediction model in the characteristic peak, the correlation coefficients of CO characteristic peak linear prediction model established by Raman spectroscopy and near infrared spectroscopy were 0.947 2 and 0.996 2, respectively. When using partial least squares (PLS) regression method to establish the biodiesel concentration prediction model in the characteristic spectral region, the correlation coefficients (R2) of the prediction set established from the Raman and near infrared spectral characteristic regions of the blended fuel are 0.981 5 and 0.991 2 respectively, and the corresponding RMSE are 0.093 7 and 0.012 9 respectively. The results show that the biodiesel concentration prediction model based on the CO spectral region in near infrared spectroscopy can obtain more accurate prediction results in mixed fuel..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1889 (2020)
Cation Substitution-Dependent Phase Transition and Color-Tunable Emission in (Ca1-xBax)2SiO4∶Eu Phosphor Series
WANG Yu, LUO Lan, GUO Rui, SUN Chuan-yao, and GAO Ming-yuan
(Ca1-xBax)1.95SiO4∶0.05Eu (x=0, 0.1, 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0) new phosphor series were prepared by high temperature solid-state reaction at 1 170 ℃ under a reduction atmosphere for 3.5 hours in this paper. The matrix crystal structure, Eu ion valence, photoluminescence spectra and fluorescence lifetime and qu(Ca1-xBax)1.95SiO4∶0.05Eu (x=0, 0.1, 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0) new phosphor series were prepared by high temperature solid-state reaction at 1 170 ℃ under a reduction atmosphere for 3.5 hours in this paper. The matrix crystal structure, Eu ion valence, photoluminescence spectra and fluorescence lifetime and quantum efficiency had been investigated. The matrix phase constituents change as γ-Ca2SiO4 (x=0)→T phase and γ-Ca2SiO4 mixture (0＜x＜0.7) →T phase (0.7≤x＜0.9)→Ba2SiO4(0.9≤x≤1) as Ba ion content increasing. By XRD analysis, it is known that (Ca1-xBax)2SiO4 powders form solid solution phases at the Ba-rich end, which are T-phase and Ba2SiO4-phase. Precision measurement of lattice parameters had been also done to T-phase (0.7≤x<0.9) and Ba2SiO4 phase (x≥0.9). For the former phase powder, the lattice parameters would increase because coordinated numbers for M1, M2, M5 sites are increasing as Ba ion content increasing, While, change from the latter one’s lattice parameters would be neglecting. Moreover, Eu ions enter into the crystal lattice by substituting for alkaline earth ions, with a minor impact. The surveys of X-ray photoelectron spectroscopy (XPS) spectra are similar, which all show characteristic electron binding energy peaks of Ba(3p3/2), Ba(3d3/2), Ba(3d5/2), O(1s), Eu(4d) and Si(2p3/2). The high-resolution spectrum of O(1s) has two peaks, corresponding to lattice oxygen and interstitial oxygen defects (caused by Eu3+ substitution to alkaline earth ion+2), respectively. Moreover, the high-resolution XPS spectrums of the Eu(4d5/2) shows that the Eu2+/Eu3+ ratio would increase as the increasing of Ba ions in the T-phase powders, while the Eu2+/Eu3+ ratio of Ba2SiO4-phase powders is not obviously changed. Ultraviolet photoluminescence photographs show that Ca1.95SiO4∶0.05Eu (γ-Ca2SiO4 phase phosphors) could be used as red phosphors, while (Ca1-xBax)1.95SiO4∶0.05Eu (x≥0.7, T-phase (green emission centered at 455 nm) or Ba2SiO4-phase phosphors (green emission peak centered at 510 nm) could green phosphors. T-phase phosphors emission is blue shift comparing with Ba2SiO4 phase phosphor. Both T-phase and Ba2SiO4-phase phosphors are blue-shifted with the increase of x value. The brightest phosphor is (Ca0.1Ba0.9)1.95SiO4∶0.05Eu (fluorescence lifetime 571.8 ns, quantum efficiency 55%, which is the shortest lifetime and highest efficiency among the green phosphors). The high-resolution photoluminescence emission spectra of green phosphor (x≥0.7) show that that Eu2+ prefers more the site with 10 coordination than the site with 9 coordination as x value decreasing in Ba2SiO4-phase crystal (the Eu2+ activators with 10-coordination contribute more in green emission), but the site preference phenomenon is vague in the case of T-phase crystal. Overall, cation substitution (i. e. controlling the x value) should be a valid way to adjust the phase constituent, lattice, ion valence, photoluminescence CIE value and intensity for the phosphor..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1895 (2020)
Space-Spectrum Joint Anomaly Degree for Hyperspectral Anomaly Target Detection
ZHANG Yan, HUA Wen-shen, HUANG Fu-yu, WANG Qiang-hui, and SUO Wen-kai
With the continuous development of hyperspectral image technology, spectral resolution and spatial resolution are continuously improved, and finer spectral features can be obtained compared to other remote sensing images. This provides a theoretical platform for the research fields of high-precision classification, demWith the continuous development of hyperspectral image technology, spectral resolution and spatial resolution are continuously improved, and finer spectral features can be obtained compared to other remote sensing images. This provides a theoretical platform for the research fields of high-precision classification, demixing and target detection of features, in which the hyperspectral anomaly target detection technology does not require a priori information of the features, which is more in line with the needs of practical applications, and has become a research hotspot. For most hyperspectral anomaly target detection algorithms, only focusing on the spectral difference between the target and the backgroundand neglecting the difference in spatial structure between the two to result in low detection accuracy, a space-spectrum joint anomaly degree for hyperspectral anomaly detectionalgorithm is proposed. The algorithm does not need to assume the background model of the image, based on the sliding double window, and proposes two concepts of the spectral anomaly and spatial anomaly. In the calculation of spectral anomaly, the nonlinear characteristics between the bands are considered, and the kernel function method based on spectral angle matching is used for detection. Based on the two-window model, the nuclear spectral angles of the central pixel and the local background pixel are calculated one by one and set. The threshold value is used to obtain the spectral anomaly of the central pixel; in the calculation of the spatial anomaly, due to the spatial clustering property of the matter, the image block gray vector representing the pixel class can be obtained by constructing the spatial window model of the pixel point. At the same time, the Euclidean distance of the image block gray vector between different pixels is solved and the threshold is set to obtain the spatial anomaly of the central pixel. Finally, the spectral anomaly of the central pixel and the spatial anomaly are summed to obtain the center. The spatial anomaly joint anomaly of the pixel, based on the sliding double window model, detects the pixels of the whole image one by one, and the abnormal detection result of the image can be obtained. The simulation results of the proposed algorithm are carried out by using three sets of real hyperspectral data of AVIRIS, and compared with the traditional RX algorithm, LRX algorithm and KRX algorithm. The results show that the proposed algorithm has better detection effect, compared with KRX algorithm. The running speed has a large increase..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1902 (2020)
Simultaneous Non-Destructive On-Line Detection of Potato Black-Heart Disease and Starch Content Based on Visible/Near Infrared Diffuse Transmission Spectroscopy
DING Ji-gang, HAN Dong-hai, LI Yong-yu, PENG Yan-kun, WANG Qi, and HAN Xi
The incidence of black-heart disease in post-harvest storage and transportation of potato in China is high, the internal quality is also uneven, and the detection and sorting technology lags behind, which seriously restricts the development of potatoes’ staple food industry. Simultaneous online non-destructive testing The incidence of black-heart disease in post-harvest storage and transportation of potato in China is high, the internal quality is also uneven, and the detection and sorting technology lags behind, which seriously restricts the development of potatoes’ staple food industry. Simultaneous online non-destructive testing of internal quality such as potatoes’ black-heart disease and starch content is of great significance for promoting the strategy of main potato diet in China. Based on the principle of visible/near-infrared diffuse transmission spectroscopy, this study uses a non-destructive on-line detection system built by the laboratory (detection speed is about 4/s), and carries out black heart disease with potato black-heart disease and starch content as internal quality test indicators. Simultaneous non-destructive testing with starch content. The original spectra of 121 healthy potatoes and 116 black-heart potatoes in the 600～1 000 nm band were averaged. The absorbance values of black potato samples in the 600～900 nm band were significantly higher than those of healthy potato samples, and the influence of black heart tissue was observed. The characteristic absorption peak of chlorophyll near 663 nm and the characteristic absorption peak of water near 760 nm of healthy potato were significantly higher than that of black heart potato. Partial Least Squares Discriminant Analysis (PLS-DA) was established based on the original spectrum of healthy potato and black heart potato. At the same time, SG-Smoothing, Standard Normal Transformation (SNV), Multiple Scattering Correction (MSC), First Derivative (FD), SG Smoothing and First Derivative (SG+FD) and other pretreatment methods were applied to the 121 healthy potato spectra. And combined with CARS algorithm to screen the characteristic wavelength, established a Starch Content (SC) Partial Least Squares (PLS) quantitative prediction model. The results showed that the correctness rate of the correction set and verification set of the PLS-DA model of the black-heart potatoes was 97.74% and 98.33%, respectively, and the total discriminant correct rate was 97.89%. The original spectrum was preprocessed by SG smoothing plus first derivative, and then combined with CARS. The PLS model of potato starch content was optimized by algorithm screening. The correlation coefficients of the calibration set and prediction set were 0.928 and 0.908, respectively, and the root means square error was 0.556% and 0.633%, respectively. Finally, the model was built into an online inspection system and externally verified using 50 samples that were not modeled. The correct rate of potato black heart disease was 96%, the correlation coefficient between the starch predicted value and the standard physical and chemical value was 0.893, and the root means square error was 0.713%. It is indicated that potato black-heart disease and other internal quality can be simultaneously detected by on-line non-destructive testing based on potatoes’ diffuse transmission spectroscopy, which provides a technical reference for potatoes’ post-harvest qualities testing and promotion of potatoes’ staple food industry..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1909 (2020)
Quantitative Analysis of Dissolved Gases in Transformer Oil Based on Multi-Parameter
CHEN Xin-gang, FENG Yu-xuan, LI Chang-xin, CHEN Shu-ting, CHEN Xiao-qing, LONG Yao, and CHEN Lin-chi
The rapid and accurate detection of characteristic gases(H2, CO, CO2, CH4, C2H4, C2H6, C2H2) in oil is an important part of transformer on-line monitoring. Laser Raman spectroscopy is suitable for the detection of characteristic gases and can overcome many shortcomings of traditional on-line monitoring. When the characThe rapid and accurate detection of characteristic gases(H2, CO, CO2, CH4, C2H4, C2H6, C2H2) in oil is an important part of transformer on-line monitoring. Laser Raman spectroscopy is suitable for the detection of characteristic gases and can overcome many shortcomings of traditional on-line monitoring. When the characteristic gas in transformer oil is detected, the characteristic peaks of methane (CH4) and ethane (C2H6) gather in the Raman spectrum from 2 900 to 3 300 cm-1. It is of great significance to study the mixed gases samples with different content ratios in this spectrum for the quantitative analysis of mixed gases in transformer oil. Based on the research of Raman spectroscopy detection of single characteristic gas, the spectral peak height, full-width at half-maximum and spectral peak area parameters of the characteristic peaks in the pretreated spectrum are selected as the characteristic factors to quantitatively analyze the mixed gas in the transformer oil. According to the second-order perturbation theory, there are four characteristic peaks in the methane Raman spectrum, and the selected spectrum contains two peaks with 3 111 and 3 284 cm-1 as the Raman shift center. Six characteristic peaks exist in the Raman spectra of ethane, and there are two peaks of 3 111 and 3 187 cm-1 in the selected spectral bands. In theory, the amount of both gases can be calculated by the information of the characteristic peak carried in the spectrum bands. Through the detection of Raman spectroscopy platform, the characteristic peaks of the mixed gas spectrum will produce translation and polymerization. In practice, four peaks with shifts center of 1 902, 2 918, 2 956 and 3 022 cm-1 were found in the spectrum. A Gaussian function model was established for the four mixed peaks, and the spectral peak height, full-width at half-maximum and spectral peak area of the characteristic peak was obtained. A partial least squares regression model (PLS) was established. The spectral peak height, full-width at half-maximum and spectral peak area were taken as independent variables, and the two gas contents were taken as dependent variables for calculation and analysis. When the potential factor of the model is taken to t6, the adjusted R-square is 0.993, indicating that the independent variable has a definite relationship with the dependent variable, and the regression model is reliable. The analysis of regression equation parameters shows that the full-width at half-maximum of spectral peaks contribute significantly to the area and height of spectral peaks, which is in line with the expected target. Four characteristic spectral peaks in the spectrum of mixed gases have an effect on both gases. It can be concluded from the experiments that for the methane-ethane mixed gas, at room temperature 25 ℃, integration time 15 s, integral number 2, slit 100 μm, by obtaining the peak height, peak area and full-width at half-maximum three parameters, the gas content can be accurately measured, which lays a foundation for the simultaneous detection of various characteristic gases in transformer oil..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1916 (2020)
Research on Spark Spectrum Signal Processing Based on Ensemble Empirical Mode Decomposition
LI Ming, LI Yan-bing, ZHANG Qiao-chu, SHI Yu-tao, CUI Fei-peng, and ZHAO Ying
The spark spectrometer based on Charge Coupled Device (CCD) is a kind of spectrometer which is used for element composition analysis. Its output signal is a composite signal of high-frequency CCD effective signal and low-frequency background noise. The effective information of spark spectrum is mainly concentrated in tThe spark spectrometer based on Charge Coupled Device (CCD) is a kind of spectrometer which is used for element composition analysis. Its output signal is a composite signal of high-frequency CCD effective signal and low-frequency background noise. The effective information of spark spectrum is mainly concentrated in the higher frequency band of signal, which is easy to be submerged and interfered by background noise. Therefore, in order to obtain complete and effective spectral information, it requires effective signal processing. Empirical Mode Decomposition (EMD) method can analyze signals adaptively without setting parameters, but there is the problem of mode mixing, and the components of different frequencies in the signal may be confused; Ensemble Empirical Mode Decomposition (EEMD) successfully solves the problem of mode mixing in EMD method, It can more clearly decompose the different frequency components in signal, so it is more suitable for processing spark spectrum signal with dispersive frequency components. In this paper, the spark spectrometer is used to excite and collect the stainless steel standard samples (Carbon C, Manganese Mn, Nickel Ni, Chromium Cr and Aluminum Al, which are representative elements in the short, medium and long band), and the original spark spectrum signals of the standard samples are obtained. Through the adaptive analysis and processing of EEMD method, each CCD signal is obtained 11 order Intrinsic Mode Function (IMF). According to the amplitude and frequency characteristics of the signal, IMF1-IMF2 is characterized as the high-frequency characteristic signal component, and the last IMF11 is the low-frequency background noise component. By reconstructing the processed signal and combining with the continuous wavelet transform-penalizedleast squares, the final processed signal is obtained. The processed signal is introduced into the instrument data processing software, and the content gradient curve of Carbon, Manganese, Nickel, Chromium and Aluminum elements is obtained. The results show that the signal processed by EEMD method is equivalent to the original instrument processing method, but the additional link of collecting blank noise section is omitted, and the analysis time is largely saved, so the operation efficiency of the instrument is improved..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1923 (2020)
Rapid Analysis of Phthalate Esters in Plastic Toys by Laser Raman Technology
XU Xin-xia, SHEN Xue-jing, YANG Xiao-bing, CHEN Ji-wen, ZHAO Meng-di, LIU Jia, ZHAO Ying, CUI Fei-peng, and LI Xiao-pen
Many plastics can be used to make toys, such as polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), etc. A certain amount of plasticizer will be added to the plastics in production, in order to make the toys have better ductility and formability. It is generally known that the phthalate esters (PAEs) are wiMany plastics can be used to make toys, such as polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), etc. A certain amount of plasticizer will be added to the plastics in production, in order to make the toys have better ductility and formability. It is generally known that the phthalate esters (PAEs) are widely used plasticizers in toy plastics. The common PAEs are diethylhexylphthalate (DEHP), dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP). Research suggests that the molecular structure of the PAEs is similar to estrogen, so the PAEs is also called “environmental hormone”. The PAEs can cause endocrine disorders, affect male reproductive ability, promote premature female puberty, and endanger children’s reproductive system in long-term or high concentration environments. Beijing Customs pointed out that the proportion of excessive PAEs was the largest in the unqualified toys. Therefore, sampling inspection is needed to ensure safety in the import and export of toys. The current standard test method of PAEs in toy plastics in China’s Customs has some shortcomings, such as complex pre-treatment process, expensive testing equipment and high professional requirements for operators, which is not conducive to the rapid detection of the PAEs and seriously restricts the rapid customs clearance of toys. Therefore, it is urgent to develop a rapid and accurate method to detect the PAEs content in toy plastics. The purpose of this paper is to establish a rapid screening technology for the PAEs in toy plastics. Firstly, the molecular configurations of DEHP, DBP and BBP were optimized, and the molecular vibration spectra were calculated by density functional theory (DFT). On this basis, the Raman spectra of DEHP, DBP and BBP measured by laser Raman technology were identified and the molecular vibration modes were assigned. This result is reliable and consistent with the actual spectral data. It shows that this method can correctly assign the characteristic peaks of Raman spectra of PAEs molecule and can be used for qualitative analysis of DEHP, DBP and BBP. Secondly, we studied the method of rapid and direct quantitative determination of the PAEs in plastics by Raman spectrometer. The results showed that the content of the DEHP, DBP and BBP were linearly correlated with the intensity of its characteristic peak, and the correlation coefficient was 0.98, 0.99 and 0.99, respectively, which indicated that the method had a high accuracy in quantitative analysis of the PAEs. Finally, the laser Raman spectrometer was used for the first time to test toy samples on the market without any pretreatment. The Raman spectra of children’s toys were obtained by optimizing the background subtraction method in the collection process. The type of the PAEs was identified as the DEHP by characteristic peaks, and the content of the DEHP was calculated. Meanwhile, the type and content of the PAEs in toy plastics were further detected by GC-MS. The consistency of the two methods was satisfactory. In conclusion, the rapid detection of the types and contents of the PAEs in plastic toys by laser Raman technology can shorten the detection time of plasticizers in children’s toys without damaging toys, and save testing costs. This method can also be applied to the qualitative and quantitative analysis of the PAEs plasticizer in other solid samples, and it is expected to be applied to the customs site to improve customs clearance speed..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1929 (2020)
Optimized Filter Selection for Measuring Copper and Molybdenum Contents by EDXRF
CAI Shun-yan, ZHOU Jian-bin, TUO Xiao-guo, and YU Jie
In the process of quantitative analysis of low content of Cu and Mo in molybdenum-copper ore by energy dispersive X-ray fluorescence spectrometry, the original spectrum of X-ray tube has a great influence on the measurement results. In order to reduce this effect, Monte Carlo software was used to simulate the influenceIn the process of quantitative analysis of low content of Cu and Mo in molybdenum-copper ore by energy dispersive X-ray fluorescence spectrometry, the original spectrum of X-ray tube has a great influence on the measurement results. In order to reduce this effect, Monte Carlo software was used to simulate the influence of filters of Ag, Cu+Mo and Ti on the original spectrum under different thickness conditions. The simulation results showed that the effect of measuring copper and molybdenum elements with 1mmTi filter is better than that of 0. 2mm Ag filter, which is better than the case of using 0.02 mm Cu and 0.1 mm Mo as filters. According to the simulation results, the thickness of the three kinds of filters was measured. By comparing atlas of spectrolines showed that When Cu+Mo is used as a filter to measure molybdenum, the background count is greater than 200, and when using Ag and Ti as a filter, the molybdenum element is measured, and there is almost no background influence. However, for the same sample, the highest count of molybdenum was about 800 when Ti was used as the filter, and the highest count of molybdenum was about 300 when using Ag as the filter. It can be seen that when the molybdenum element is measured by using Ti as a filter, the original spectrum of the X-ray tube has little influence on the interference of the measuring element, and the background thereof is lower than that of the silver filter and the copper-molybdenum filter. The Ti filter has the highest count rate of molybdenum while reducing the background effect, indicating that the ray strength loss is the least. When Cu+Mo is used as a filter to measure copper, the highest count of copper is 300. When using Ag as a filter, the highest count of copper is about 180, while the highest count of copper using the filter is about 500. It can be seen that when the content of copper is low, the use of Ti as a filter to measure copper elements has the highest count rate of copper and the least loss of ray strength. The calculation by formula showed that the detection limit of copper in molybdenum-copper ore is 5.63 mg·kg-1 with 1 mm Ti filter, and the detection limit of molybdenum is 1.39 mg·kg-1, and the detection limit is significantly reduced. Using different standard samples for measurement andchemical analysis fitting, the working curve shows that the high and low content samples have a good linear relationship, the error level meets the normal chemical analysis error standard, R2 is 0.99 and above, indicating that 1 mm Ti is passed. The measurement results by using 1 mm Ti filter are highly Precision. Selecting any one of the production samples for repeated measurements, the RSD (%) of the Cu element is 0.59, and the RSD (%) of the Mo element is 0.3, which is less than 1, indicating that the instrument has good measurement stability and the sample test results are reproducible. In this paper, the determination of molybdenum and copper in molybdenum copperore by energy dispersive X-ray fluorescence spectrometry, Monte Carlo simulation analysis provides a credible basis for the selection of filters and the determination of their thickness. A 1 mm Ti filter was selected and tested on-site. The method is stable and reliable and has important practical application value..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1934 (2020)
Hyperspectral Imaging Technique for Estimating the Shelf-Life of Kiwifruits
SHAO Yuan-yuan, WANG Yong-xian, XUAN Guan-tao, GAO Zong-mei, LIU Yi, HAN Xiang, and HU Zhi-chao
The shelf-life of fruits and vegetables is an important factor that affects the quality, which is concerned by the consumers, farmers and producers. Kiwifruit contains a variety of organic substances and amino acids, which has rich nutritional value and is deeply loved by consumers. However, due to its own characteristThe shelf-life of fruits and vegetables is an important factor that affects the quality, which is concerned by the consumers, farmers and producers. Kiwifruit contains a variety of organic substances and amino acids, which has rich nutritional value and is deeply loved by consumers. However, due to its own characteristics such as the color characteristics of kiwifruit, it is difficult for consumers to make an accurate judgment on the edible degree of kiwifruit in the shelf-life by sensory evaluation. Therefore, non-destructive testing of the shelf life of fruits and vegetables is vital for agricultural products. In this research, hyperspectral imaging technology with chemometric methods was employed to estimate the shelf-life of kiwifruits which were stored in 4 ℃ and (18±2) ℃ among 3 periods (0, 2, 4 d). The spectral data covering the range of 400～1 000 nm were collected from 720 kiwifruit samples of 3 periods at 4 ℃ and (18±2) ℃. Meanwhile, the firmness and solid soluble content (SSC) of kiwifruits were measured, and the spectral data of kiwifruit slices were collected. The mean spectra (90 kiwifruits in the training set and 30 kiwifruits in prediction set) were extracted from each kiwifruit. Then, principal component analysis (PCA) was implemented for samples stored at different temperatures. Cluster analysis was performed based on PC1, while some overlap phenomenon showed in kiwi samples at 4 ℃. X-loadings of principal component analysis (PCA) and successive projection algorithm (SPA) method were applied to select the effective wavelengths, which are helpful for enhancing computer velocity. Based on X-loadings, 7 wavelengths (481, 501, 547, 665, 723, 839, 912 nm) were selected for samples stored at 4 ℃ and 7 wavelengths (508, 545, 665, 672, 720, 839, 909 nm) were selected for samples stored at (18±2) ℃, respectively. Similarly, for the SPA method, 10 wavelengths (406, 428, 520, 617, 665, 682, 723, 818, 878, 983nm) were selected for samples stored at 4 ℃ and 10 wavelengths (575, 622, 731, 756, 779, 800, 828, 865, 920, 983 nm) were selected for samples stored at (18±2) ℃, respectively. Thereafter, virtual levels (1, 2, 3) were assigned to the samples of 3 periods at 4 ℃ and (18±2) ℃, respectively. Least square-support vector machine (LS-SVM) was used to build classification models on full spectral data, effective wavelengths selected based on PCA and SPA, respectively. The results showed that the accuracy of the predictions reached to 92.2%, 92.2% and 91.1% among 3 periods at 4 ℃ and the accuracy of the predictions reached to 100% among 3 periods at (18±2) ℃, respectively. Also, the firmness and SSC of kiwifruits were measured and analyzed by one-way analysis of variance (ANOVA), the results showed that there was a negative correlation between firmness and shelf-life and the correlation coefficient was -0.335 6 and -0.562 0 at 4 ℃ and (18±2) ℃, respectively. There was a positive correlation between SSC and shelf-life and the correlation coefficient was 0.557 6 at (18±2) ℃. The shelf-life of kiwifruits can be estimated by the firmness index of samples stored atboth 4 ℃ and (18±2) ℃. While the SSC of samples stored at (18±2) ℃ was a significant estimation index. Further, the images of PC1-PC7 can preserve the integrity of the kiwifruit slice surface information, PC2 image can clearly show the degree of kiwifruit slices with different shelf-life. The results of this study indicate that it is feasible to use the hyperspectral imaging technique combined with the chemometric methods to classify the shelf-life of kiwifruits. Meanwhile, this research realized the rapid prediction of the shelf-life of kiwifruits and provided theoretical support for the quality and classification of fruit and vegetable shelf-life. Further, this study help forproviding technical supports for the developed instruments used for real time estimating the shelf-life of fruits and vegetables in further study..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1940 (2020)
A Circular Scanning System of Laser-Induced Breakdown Spectroscopy for Tracking the Element Distribution
LAN Yun-jiao, LU Yuan, GUO Fei, GUO Jin-jia, and ZHENG Rong-er
Laser-induced breakdown spectroscopy (LIBS) is a rapid method for elemental analysis with significant advantages of sample-less, in situ, non-contact, multi-element detection, etc., and it has been widely applied in many research fields. In this work, LIBS was employed to develop a system for circular scanning, which cLaser-induced breakdown spectroscopy (LIBS) is a rapid method for elemental analysis with significant advantages of sample-less, in situ, non-contact, multi-element detection, etc., and it has been widely applied in many research fields. In this work, LIBS was employed to develop a system for circular scanning, which can obtain the location of the high concentration region of elements according to the distribution acquired from the detection results of scanning. Based on this, an effective, fast and real-time method was provided for environmental anomaly monitoring, pollution source tracking and even mineral exploration. A simple structure was brought in that system to enable 360-degree scanning via rotating optics, not moving the entire system. The position or the orientation of the high concentration region (source) could be tracked by referencing the element distribution, which is related to the signal intensity of LIBS detection. In order to verify the concept of LIBS circular scanning and to evaluate the detectability of the system, seawater fog rich in elements of potassium, calcium, sodium, magnesium was used for the sample to simulate the source eruption. And detection of 360-degree scanning was carried out to evaluate the detection response with an interval of 10 degrees. Experimental results showed that the source position or orientation could be found accurately by following elements distribution, while necessary calibration was required to correct the detection result. The correction procedure includes two aspects: correction of fluctuant data and detection efficiency. The former is used to reduce the signal instability in the process of LIBS detection, mainly through the selection of internal reference elements to modify the signal fluctuation. The latter aims to reduce the errors in the detection process resulting from the installation and debugging and modify the acquisition efficiency of each scanning position according to the detection results in the even atmosphere. The corrected annular scanning data showed that the system could accurately obtain the location of “eruption source” with a large scanning radius (250 and 300 mm). In addition, the exact orientation of the area with a high concentration of elements can be found at a distance from the eruption location with a short scanning radius (100 mm). Therefore, it is suggested that LIBS could be functioning as a “radar” for circular scanning. The distribution of elements obtained through LIBS detection can accurately confirm the exact position of the source by identifying the high concentration region, so as to achieve the purpose of target source tracking..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1947 (2020)
The Study of Raman Spectroscopy of Bifenthrin Molecular
LIAN Shuai, CHEN Bin, GU Yi-fan, SONG Chao, LEI Jun-jie, and GAO Xun
Bifenthrin is a type Ⅰ pyrethroid pesticide, which is widely used in agricultural production due to its good efficacy, rapid action and easy degradation. However, bifenthrin pesticide residues have lethal toxicity to beneficial insects, aquatic animals, endocrine disrupting effects on humans, estrogen effects, and persBifenthrin is a type Ⅰ pyrethroid pesticide, which is widely used in agricultural production due to its good efficacy, rapid action and easy degradation. However, bifenthrin pesticide residues have lethal toxicity to beneficial insects, aquatic animals, endocrine disrupting effects on humans, estrogen effects, and persistence in multiple organs such as the liver, which are seriously harmful to human health. Density functional theory is a mathematical ab initio calculation method that can be used to calculate molecular orbitals and Raman spectra. Density functional theory is a mathematical ab initio calculation method that can be used to calculate molecular orbitals and Raman spectra. Combining density functional theory and Raman spectroscopy to study materials is currently the most commonly used Raman spectroscopy research method. In this paper, the B3LYP/6-31G basis set of density functional theory was used to optimize the molecular configuration of bifenthrin and calculate its theoretical Raman spectrum. In the experiment, a laser having a wavelength of 785 nm was used as the excitation light, and a spontaneous Raman spectrum of the pure solid of bifenthrin analysis was obtained. By comparing the theoretical Raman spectroscopy and experimental Raman spectroscopy of bifenthrin, the vibration mode of bifenthrin molecules is analyzed and attributed. The molecular structure of bifenthrin is relatively complex, it has more vibration mode, and the Raman peak is more complicated. A peak with relatively strong Raman activity at 659, 948, 993 and 1 292 cm-1 was found as a characteristic peak for the identification of bifenthrin, and the bifenthrin molecules can be qualitatively and quantitatively classified according to these characteristic peaks. The results show that the theoretical Raman spectra of bifenthrin and the experimental Raman spectroscopy have good matching, but there is a certain degree of shift in the wave number of the characteristic peaks. This is due to the fact that the object of the theoretical calculation is the gaseous monomolecular of bifenthrin, and the complex intermolecular interaction and inter-group interaction exist in the bifenthrin solid. At present, there are relatively few studies on the molecular vibration mode and Raman spectroscopy of bifenthrin, and the bifenthrin pesticide residue has also attracted much attention in recent years. The research results provide a qualitative and quantitative analysis of bifenthrin pesticide residues. A new feasible method and lay the foundation for rapid detection of pesticide residues on crop surfaces..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1952 (2020)
Improvement of Hyperspectral Estimation of Nitrogen Content in Winter Wheat by Leaf Surface Polarized Reflection Measurement
LIN Yi, LIU Si-yuan, YAN Lei, FENG Hai-kuan, ZHAO Shuai-yang, and ZHAO Hong-ying
Hyperspectral remote sensing provides an effective way for real-time prediction of plant nitrogen content (PNC) in winter wheat plants. In hyperspectral detection, energy received by the sensor is divided into unpolarized light, which comes from multiple scattering inside the plant, and partially polarized light, whichHyperspectral remote sensing provides an effective way for real-time prediction of plant nitrogen content (PNC) in winter wheat plants. In hyperspectral detection, energy received by the sensor is divided into unpolarized light, which comes from multiple scattering inside the plant, and partially polarized light, which is from the foliar surface, while the latter does not contain nitrogen content information. This paper aims to evaluate the influence of this part of the surface polarization reflection on the PNC estimation. The canopy bidirectional reflectance factor (BRF) in nadir direction of 48 plots in periods of jointing, flagging, flowering and grouting of winter wheat were obtained, and the polarization component was assembled in front of the spectrometer fiber. The polarized reflectance (pBRF) is obtained, and the diffused reflectance factor (dBRF), which partially removes the surface reflection, is obtained by removing the pBRF from the BRF. Using spectral regression and vegetation index (VI) methods, the results of BRF, dBRF, and the existing methods considering removing surface reflection, were compared, to prove the effectiveness and stability of the polarization method. Evaluate the correlation between PNC and BRF & dBRF spectrum; in the spectral regression method, interval partial least squares regression (iPLSR) was used for PNC estimation. The method considering first-order derivative BRF (derBRF) was also compared. For the VI method, the PNC-VI models were established by using 7 VIs. The existed modified VI (mVI) models were also compared for analysis of the advantages and stability of the polarization-dBRF method. Finally, the non-negligibility of polarization reflection, the accurate estimation of surface reflection and the main error sources of the experiment were discussed and analyzed. After the removal of the polarized reflection, the correlation between the reflectance spectrum and PNC is significant in the visible band. The correlation coefficient increased from 0.68 to 0.72 in the blue band and slightly increased in the other spectral regions. In the spectral regression method, the root means square error RMSE of the predicted-measured PNC and dBRF spectrum reduced from 0.30% to 0.23%, indicating 23%’s error reduction; the estimation result is better than derBRF. The method demonstrates the effectiveness of the polarization method. In the vegetation index method, the accuracy of the PNC estimation model of the 7 VIs after polarization removal is slightly improved, and the result is better than the mVI method, which proves the stability of the polarization method. The ND680 (NDVI), ND705 and OSAVI indices yielded better PNC estimation in flowering and grouting periods, with the modeling relative RMSE (RRMSE) within 11%; SR705 and NDNI performed the best in jointing and flagging periods, with the modeling RRMSE within 13%. This study provides a reference for improving the accuracy of remote sensing retrieval of vegetation components..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1956 (2020)
Monitoring of Corn Canopy Blight Disease Based on UAV Hyperspectral Method
LIANG Hui, HE Jing, and LEI Jun-jie
Blight disease is a serious disease for corn. Therefore, there is an urgent need for a method for quickly understanding the condition of corn blight disease. In this study, UAV remote sensing is used as a new technology platform to explore the spectral response of corn canopy under the stress of blight disease, and UAVBlight disease is a serious disease for corn. Therefore, there is an urgent need for a method for quickly understanding the condition of corn blight disease. In this study, UAV remote sensing is used as a new technology platform to explore the spectral response of corn canopy under the stress of blight disease, and UAV hyperspectral imaging technology is used to monitor and visualize the disease of blight disease. Therefore, this study collected data on corn growth stages (the tasseling period, the filling period, the maturity period), and used the UAV hyperspectral instrument to acquire the hyperspectral image of the canopy 500～900 nm. This research based on the original spectra and first-order differential spectral features of the acquired images, the position of the 12 sensitive spots of the blight disease was extracted. The positions of the 12 bands were: 514, 532, 553, 680, 714, 728, 756 and 818 nm, near-infrared, red, green and red edge positions. At the same time, based on the plant disease monitoring parameters proposed by the predecessors combined with the extracted sensitive band positions, 13 sets of monitoring spectral parameters for corn canopy blight disease were constructed. In this way, the sensitivity of different bands to the disease index (DI) value of blight disease was studied, and a monitoring model for monitoring corn canopy blight disease was constructed to verify the accuracy and stability of using the UAV remote sensing technology to monitor the DI value of blight disease. The results show that with the increase of the disease index, the first-order differential spectrum shows a typical “blue shift” phenomenon, and the correlation between the disease canopy DI value and the red (680～714 nm) and near-infrared (770～818 nm) reflectance and the red edge position (680～756 nm) of the first-order differential spectrum is more significantly, the correlation with the green band is low. Among the 13 groups of monitoring spectral parameters, 8 groups and the modeled canopy blight disease measured the DI value reached a very significant correlation level, R2 all reached above 0.8. Therefore, in this study, the spectral parameters of R2 with a growth period of 0.8 or higher were selected for the construction of the corn canopy blight disease monitoring model, and the correlation between the measured values of the test samples and the predicted values of the monitoring models was analyzed. The test shows that in the tasseling period, the regression slope (0.829 3) and the decision coefficient (R2=0.842 7) of the model DI-NDVI(SDλi, SDλj) are closest to 1, and the root mean square error (RMSE=4.59) and relative error (RE=12.3) are smaller, indicating that the prediction ability and accuracy of the model DI-NDVI(SDλi, SDλj) are higher than others. The results show that the corresponding models in each growth period have achieved good monitoring results, indicating that the research using UAV remote sensing has guiding significance for plant disease monitoring, and has certain reference value for the development of precision agriculture..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1965 (2020)
Error Analysis of the New Measurement Technique for Obtaining the Spectral Diffraction Efficiencies of a Grating
WANG Sheng-hao, SHAO Jian-da, LIU Shi-jie, LI Ling-qiao, WU Zhou-ling, CHEN Jian, and HUANG Ming
Diffraction grating is a very important dispersive element, and it has been commonly used in the field of spectral analysis, the measurement of a diffraction grating’s spectral diffraction efficiencies is essential for evaluating its performance in practical applications and improving its manufacturing technique. In thDiffraction grating is a very important dispersive element, and it has been commonly used in the field of spectral analysis, the measurement of a diffraction grating’s spectral diffraction efficiencies is essential for evaluating its performance in practical applications and improving its manufacturing technique. In the currently popular measurement technique for obtaining the spectral diffractionefficiencies of a plane grating, because of the hundreds of repetitions of two kinds of time-consuming mechanical movements during the measuring process, the major drawback of this technique is the slow measuring speed, for example, approximately 5-8minutes are needed to obtain the spectral diffraction efficiencies of a broad band pulse compression gratings from 700 to 900 nm (in sampling steps of 1 nm). In our earlier research, we presented a motionless and fast measurement technique for obtaining the spectral diffraction efficiencies of a plane grating, and the new method was based on the employment of an acousto-optical tunable filter, an integrating sphere and a fast data acquisition system, the new methodcan measure the plane grating’s spectral diffraction efficiencies (in the wave range of 700～900 nm) successfullyon a milli second time scale without the involvement of mechanical movements. In this paper, firstly, we analyze the error source of the new measurement method, and we find that the major error source is that the transmittance of the convex lens is a function of the incident angle; then, based on optical simulation, we obtain the relationship of the convex lens’s optical transmittance versus the incident angle, and meanwhile propose the method to correctthe error; finally, based on the experimental result, the error correction method is experimentally tested. Data analysis result demonstrates that, in the wave range of 700～900 nm, the mean absolute error between the two measured spectral diffraction efficiencies by using the new and the currently popular methods has been decreased from 0.207% (before error correction) to 0.099% (after error correction), considering the measurement accuracyof the currently popular method is around 0.1%, we think the error correction method provided in this paper can successfully eliminate the main error source of the new measurement technique for obtaining the spectral diffraction efficiencies of a grating..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1973 (2020)
High-Quality UV-Vis Spectrum Signal Reconstruction Algorithms Based on Binary Search
ZHU Hong-qiu, HU Hao-nan, ZHENG Guo-liang, ZHOU Can, and LI Yong-gang
In the background of high zinc, when the concentration of trace polymetallic ions is simultaneously measured by spectroscopy, the energy radiation of the light source of the micro-spectrometer is not uneven, and different ions in the mixed solution can selectively absorb the ultraviolet-visible light at different bandsIn the background of high zinc, when the concentration of trace polymetallic ions is simultaneously measured by spectroscopy, the energy radiation of the light source of the micro-spectrometer is not uneven, and different ions in the mixed solution can selectively absorb the ultraviolet-visible light at different bands. Therefore, too long integration time may lead to the saturation of spectral energy value, and if the integration time is insufficient, the signal-to-noise ratio of the spectral signal may be very low. The selection of integral time depends on the existing experience of researchers and the characteristics of the UV-Vis spectral signals of ions to be measured. In order to automatically select the integral time of micro-spectrometer, a high-quality UV-Vis spectral signal reconstruction algorithm based on the binary search is proposed to reconstruct the UV-Vis spectral signal with more distinct characteristics composed of different integral time. Firstly, the UV-Vis spectral energy reference solution is collected at the different integral time. Then the spectral energy signal target values of the reference solution are given, and the appropriate integral time sampling parameters are found at each wavelength point by using the binary search algorithm. Next, according to the characteristics of UV-Vis spectrum, the reconstruction accuracy index which is determined to represent the degree of proximity between the reconstructed spectral energy value and the target setting value and the feature saliency index which is used to indicate the degree of feature saliency before and after signal reconstruction are defined. Finally, the spectral signal with the highest reconstructed accuracy in the search interval is selected as the reconstructed information. The reconstructed information is used to reconstruct the UV-Vis spectral energy value of the solution to be measured. The reconstructed spectral absorbance signal of the solution to be measured is obtained at the end. The experimental results show that the proposed algorithm can quickly and automatically select the lintegral target time to reconstruct the UV-Vis spectrum signal, and to obtain high quality UV-Vis spectrum signal. The accuracy of signal reconstruction can reach 94.84%, and the reconstructed feature is improved significantly. At the same time, the absorbance signal of the reconstructed UV-Vis spectral signal is enhanced. Compared with the UV-Vis spectral signal before reconstruction the signal-to-noise ratio of the spectral signal after reconstruction is greatly improved, and the problem of choosing the parameters of integral time based on the subjective judgement of researchers is avoided. It provides high quality model data for detecting the concentration information of various trace metal ions..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1979 (2020)
An Estimation Study to Determine the Percentage of Hydroquinone Levels in situ Skin Lightening Creams Using GC-MS and HPLC Spectroscopic Instruments
Maha Abdallah Alnuwaiser
Hydroquinone (HQ) is an phenolic aromatic compound used in cosmetic medicine as skin lightening material since long time ago. Accordingly the several pathological conditions that observed, the use of HQ for this purpose was recently contraindicated. The commonly noted health problem associated with hydroquinone use wasHydroquinone (HQ) is an phenolic aromatic compound used in cosmetic medicine as skin lightening material since long time ago. Accordingly the several pathological conditions that observed, the use of HQ for this purpose was recently contraindicated. The commonly noted health problem associated with hydroquinone use was contact dermatitis. The present study was designed and conducted to determine the HQ presence and concentrations in ten samples of skin lightening cosmetics available in the local market. GC-MS analysis was employed for detection of HQ qualitatively while HPLC analysis was used as a quantitative analysis for determination of the HQ concentrations in each sample. The results obtained indicated that the overall range of HQ levels in all respected samples ranged from 0.003 9% to 0.14%..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1984 (2020)
Synthesis and Spectroscopic Characterizations on the Complexation of Three Different Metal Ions Ba(Ⅱ), Ni(Ⅱ), and Ce(Ⅲ) with Atenolol Drug Chelate
Samy M EI-Megharbel, Tariq Altalhi, Abdullah Ayad Salem Alruqi, and Moamen S Refat
Three types of metal ions barium(Ⅱ), nickel(Ⅱ) and cerium(Ⅲ) complexity of ATN drug have been prepared and characterized using molar conductance method, FT-IR, electronic, and 1H-NMR analysis measurements. The chemical and physical results for all atenolol complexes are agreement with the speculated structures. For theThree types of metal ions barium(Ⅱ), nickel(Ⅱ) and cerium(Ⅲ) complexity of ATN drug have been prepared and characterized using molar conductance method, FT-IR, electronic, and 1H-NMR analysis measurements. The chemical and physical results for all atenolol complexes are agreement with the speculated structures. For the divalent (Ba & Ni) and trivalent (Ce) metal atenolol a molar ratio 1∶2 was established. Qualitative chemical analysis showed that for the divalent metal complexes, the chloride ions are not involved in the complexes, suggesting that all of these complexes, ［Ba(ATN)2］·2H2O and ［Ni(ATN)2(H2O)2］·4H2O are neutral. However, for the cerium(Ⅲ) complex, ［Ce(ATN)2(NO3)］·3H2O, the nitrate group is existed inside the coordination sphere. ATN make astable metal complexity with barium(Ⅱ), nickel(Ⅱ) and cerium(Ⅲ) ions. Electronic absorption analysis of Atenolol give two fundamental peaks at 225 nm and 274 nm refers to variation in transition electrons of ligand, UV spectral analysis of the three complexity obtained give asymmetric broad band in the range 200～400 nm, the reults are convenient with the suggestion of metal-nitrogen and metal -oxygen bonds. The infrared analysis data proved that ATN act as bidentate ligand through the N atom of the -NH group and O atom of the deprotonated alcoholic OH group. Nickel(Ⅱ) and cerium(Ⅲ) complexity make six-coordinate geometry, whereas the barium(Ⅱ) complex exhibit four-coordinate geometry. Ni(Ⅱ)-ATN complex has an effective magnetic moment equal 3.12 B.M, that is assigned to octahedral structure. The 1H-NMR spectral results of Ba(Ⅱ)-ATN complexity give strong signal at ~4.00 ppm due to protons of -CH2 that influenced by low degree due to complexity. These results confirm the position of chelation through the N atom of the -NH group and O atom of the deprotonated alcoholic OH group..
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1988 (2020)
[in Chinese]
Spectroscopy and Spectral Analysis
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 6, 1 (2020)
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