DETERMINATION OF SALICYLATE-TYPE AND BENZOPHENONE-TYPE SUNSCREEN AGENTS IN COSMETIC PRODUCTS BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

A novel simple method to detect salicylate- and benzophenone-type sunscreen agents in cosmetic products by gas chromatography-mass spectrometry (GC-MS) has been developed. Seven sunscreen agents (two salicylate-type and five benzophenone-type) were used for this study. Sunscreen agents and cosmetic product solutions were prepared by dissolving in dimethylformamide, and silylated with bis-trimethylsilyltrifluoroacetamide-trichloro-methylsilane (BSTFA). Silylated sunscreen agents were separated on a cross-linked methyl silicone gum column. The identification of each sunscreen agent was accomplished by retention time and mass spectrum library search with a computer, and the quantitation was made in the selected-ion monitoring (SIM) mode of GC-MS. Silylation increased the detection limits of all sunscreen agents about 20-170-fold. Linearity was maintained over the range 1-300 mu g/ml for each sunscreen agent. Each cosmetic product (i.e. sun lotion, sun cream and sun cream foundation) was found to contain amounts of the sunscreen agents. This method was sensitive and gave 95.2-104.1% recovery of each sunscreen agent from these cosmetic products. From these results, we concluded that silylation with BSTFA followed by GC-MS analysis allows the simple, convenient and exact determination of sunscreen agents from cosmetic products.