Fig. 1. Schematic diagram of the removing of water peaks in BSA aqueous solution by two background samples

Fig. 2. Infrared spectra of 50 mg·mL^-1 BSA aqueous solutions
Air ATR 32 scans plus water ATR: a: 0 scans; b: 96 scans; c: 224 scans; d: 480 scans; e: 596 scans

Fig. 3. Comparison between the spectral subtraction and two background samples method
a: Infrared spectrum of BSA aqueous solution; b: Infrared spectrum of water; c: Difference spectrum between the two spectra of BSA aqueous solution and water; d: The spectrum of BSA aqueous solution obtained by two background samples

Fig. 4. IR spectra of BSA aqueous solutions obtained by two background samples
Heat treatment temperature: (a): 25 ℃; (b): 40 ℃; (c): 55 ℃; (d): 70 ℃; (e): 85 ℃

Fig. 5. IR spectra of BSA aqueous solutions after the removing of water peaks
Heat treatment temperature: a: 25 ℃; b: 40 ℃; c: 55 ℃; d: 70 ℃; e: 85 ℃

Table 1. The origins of the peaks for the second-order differential spectrum

Table 2. Effect of temperature on amide band Ⅰ and amide band Ⅱ of BSA in the aqueous solutions