Simultaneous determination of fifteen ultraviolet filters in sunscreen cosmetics by high performance liquid chromatography

Abstract

An analytical method for the simultaneous determination of fifteen ultraviolet (UV) filters in sunscreen cosmetics was developed by high performance liquid chromatography (HPLC). Various cosmetic samples including lotions, emulsions, creams and waxes were firstly mixed thoroughly by adding tetrahydrofuran containing 2 g/L ammonium hydroxide followed by vortex and oscillation. If the wax samples were still homogenized incompletely, a ultrasonic oscillation protocol with heating to 50 °C was adopted. The homogeneous samples were then ultrasonically extracted by 80% aqueous methanol solution. After centrifugation and micropore filtration, the extracted components were separated on an XTerra MS C18 column with gradient elution by water containing 0. 1% (v/v) formic acid and methanol containing 0. 1% (v/v) formic acid, determined by a diode array detector (DAD) at 280 nm and 311 nm, and quantified using external standard method. Optimization for the pretreatment conditions of different matrices of cosmetics including sample dispersion solvents, extraction solvents and time were carried out. This developed method showed good linearity (r2 ≥ 0.999 1) and the limits of quantification (LOQs) were between 1.2 and 5.1 µg/g. The recoveries of the fifteen compounds ranged from 84.2% to 100.7% at three spiked levels with the relative standard deviations (RSDs) between 0.9% and 9.5%. The analytes were well separated and this analytical method proved to be sensitive and accurate, so it can be used in the practical determination of the fifteen UV filters in commercial sunscreen cosmetics.