Sample solutions of different concentrations (1 mL) and 10 g/100 mL yolk homogenate (w/v) (0.5 mL)
prepared by 1.15 g/100 g KCl solution were evenly blended in the tube, added with 2 mL distilled water, 1.5 mL glacial acetic acid (20 mL/100 mL pH 3.5) and 1.5 mL TBA (0.8 g/100 mL) that contained 1.1 g/100 mL SDS, evenly mixed and then put in 95 C water bath for 60 min. After being cooled to room temperature, the samples were added with 5 mL butanol, and centrifuged at 1610 g for 10 min.