Fig. 1. Batch preparation device and effect diagram of tapered fiber SERS probes. (a) Schematic of disc with circular through holes, in which diameter and thickness of disk are 10.0 mm and 3.0 mm, and diameter and spacing of circular through holes are 400.0 μm and 2.5 mm respectively; (b) distribution of golden sphere particles on tapered surface of prepared fiber SERS probe after 2 h electrostatic adsorption with local enlarged picture of dotted box area shown in inset

Fig. 2. Experimental setup of SERS test for tapered fiber probes

Fig. 3. Detection results of tapered fiber SERS probes. (a) SERS spectra of 10^-6 mol/L thiram standard solution measured by 10 tapered fiber probes in same batch; (b) average SERS spectra of 10^-6 mol/L thiram standard solutions measured by 6 different batches of probes; (c) spectral amplitudes of Raman peaks at 1386 cm^-1 and corresponding SDs in SERS average spectra measured by 6 different batches of probes

Fig. 4. Fitted curves of spectral amplitude of Raman characteristic peak at 1386 cm^-1 for thiram solutions (square is data and line is fitted line)

Fig. 5. Quantitative curves before and after spectral data assimilation. (a) Quantitative curves before spectral data assimilation; quantitative curves after spectral data assimilation based on quantitative relationship curves of batch (b) 1, (c) 4 and (d) 8 fiber probes (square is data and line is fitted line)

Table 1. Detected concentrations of spiked samples before and after spectral data assimilation

Table 2. Detected recovery rates before and after spectral data assimilation