Determination of 4 Benzotriazole Ultraviolet Absorbents in Cosmetics by Gas Chromatography

A method for simultaneous determination of four benzotriazole ultraviolet absorbents including drometrizole (UV-P), bumetrizole (UV-326), octrizole (UV-329) and drometrizole trisiloxane (DTTSO) in cosmetics by gas chromatography was proposed. The sample (0.300 0 g) was placed in a 10 mL colorimetric tube and diluted to a scale with a mixture of methanol and tetrahydrofuran at a volume ratio of 1:2. For water-like cosmetics, the filtrate was obtained after ultrasonic extraction for 10 min. For emulsion, frost and waxy cosmetics, after vortex oscillation for 5 min, ultrasonic extraction for 10 min, and centrifugation for 2 min, the supernatant was taken. The above solution was passed through 0.45 μm organic filter membrane, and 1 mL of 4.00 g·L^-1 internal standard (DNOP) solution was added. The mixture was made its volume up to 10 mL with ethanol. Four benzotriazole ultraviolet absorbents in the above solution were separated by HP-50⁺ quartz capillary column and flame ionization detector according to column temperature program, and quantitative analysis was carried out by the internal standard method. As shown by the results, linear relationships between peak area ratios and mass ratios of UV-P, UV-326, UV-329 and DTTSO to internal standard were found in definite ranges, with detection limits of 23.64, 12.03, 39.88, 57.46 mg·L^-1, respectively. Test for recovery was made by the standard addition method, giving the results in the range of 90.6%-103%, with RSDs (n=6) of the determined values less than 5.0%. This method was applied to analysis of 12 cosmetics with different matrices, only UV-326 and UV-329 were detected in 2 emulsion cosmetics, with the detection amounts of 9.56 mg·g^-1 and 5.48 mg·g^-1.