Abstract:

A sample preparation and analytical method with liquid-liquid extraction (LLE) and high performance liquid chromatography (HPLC) was developed to detect 11 benzophenone ultraviolet-filters in cosmetics. The target compounds were extracted by the mixed solutions of tetrahydrofuran (THF)/methanol/water or dichloromethane/water at proper ratios. The extracts were centrifuged and filtered to remove matrix compounds, and then analyzed by HPLC. The separation of analytes was carried out on a Diamonsil-C18 column (150 mm×4.6 mm, 5 μm) with 0.1%(v/v) formic acid aqueous solution (containing 10 mmol/L ammonium acetate) as mobile phase A and methanol containing 0.1%(v/v) formic acid as mobile phase B. The spiked recoveries of the method (n=7) were 93.4%-103.8% with the relative standard deviations of 0.1%-4.2%. The limits of detection (LODs) were in the range of 4.0-30 μg/g and the limits of quantitation (LOQs) ranged from 15 to 100 μg/g. The method was applied to the determination of 42 cosmetic samples randomly purchased from the supermarket in Dalian. Five benzophenone series were always detected, in which the content of benzophenone-3 in sunscreen cream and the content of benzophenone-2 in perfume were very high and reached 2785 μg/g and 2106 μg/g, respectively. The results showed that the developed method is efficient, reliable and sensitive, which can be applied to the determination of benzophenones in cosmetics.

Key words: benzophenone series, cosmetics, high performance liquid chromatography (HPLC), ultraviolet-filters