Determination of 20 Sunscreen Agents in Sunscreen Cosmetics by High Performance Liquid Chromatography

0.200 0 g of sunscreen cosmetics were taken and dissolved with methanol-tetrahydrofuran-water-perchloric acid (350+550+100+0.067) solution in the 50 mL of colorimetric tube with plug. And then extracted ultrasonically for 30 min, remove 2.0 mL of the above solution and diluted it with methanol-tetrahydrofuran-water-perchloric acid (250+450+300+0.2) solution to 10.0 mL. The mixture was filtered through a filtering membrane of 0.45 μm, at least 2 mL of the primary filtrate was discarded and the secondary filtrate was taken as the liquid to be tested. The contents of 20 sunscreens were determined by high performance liquid chromatography and detected by diode array detector. As shown by the results, linear relationships between values of peak area and mass concentration of the 20 sunscreens were found in the definite ranges, with detection limits (3S/N) in the range of 0.006 0-0.28 mg·L^-1. Test for recovery by standard addition method was made on the base of negative sunscreen cosmetic sample, giving results in the range of 93.2%-107%, and RSDs (n=6) ranged from 0.10% to 1.7%.