Abstract:

An efficient high performance liquid chromatography analysis method for detecting the content of prohibited preservatives 2, 4, 6-trichlorophenol, pentachlorophenol and bithionol in exported cosmetic soaps was established. There is no literature about the determination of 2, 4, 6-trichlorophenol, pentachlorophenol and bithionol method in soaps. The sample was made into uniform crumbs, dissolved in hot water, mixed with acetonitrile for extraction, and was salted out to obtain the extracting solution. Gradient elution was carried out with methanol-acetonitrile-ammonium acetate as ternary mobile phase. It was at a flow rate of 1.0 mL/min through an Agilent ZORBAX Eclipse XDB-C₁₈ chromatographic column （5 μm, 4.6 mm×250 mm）, and the column temperature was 30 ℃. The UV detection wavelength was 300 nm. The external standard method was used for quantification. The experimental results show that the linear correlation coefficients of the three substances are more than 0.999. The limit of detection （LOD） and the limit of quantification （LOQ） of 2, 4, 6-trichlorophenol and pentachlorophenol are 1.5 and 5.0 mg/kg, respectively, and the limit of detection （LOD） and limit of quantification （LOQ）of bithionol is 0.8 and 2.5 mg/kg, respectively. Average recoveries of standard addition at three levels are in the range of 81.8% to 103.0%, with the relative standard deviation （RSD） in the range of 3.88% to 8.57% （n=6）. The method is quick, accurate and economical. It is suitable for the quick screening and quantitative analysis of 2, 4, 6-trichlorophenol, pentachlorophenol and bithionol in exported cosmetic soaps. It fills the blank of determination method of the three substance in exported cosmetic soaps, and provides testing technology support for customs supervision of exported cosmetic soaps.

Key words: prohibited preservatives, 2, 4, 6-trichlorophenol, pentachlorophenol, bithionol, salting out phase separation extraction, high performance liquid chromatography, exported cosmetics, soap