Determination of butyl methoxydibenzoylmethane, benzophenone‐3, octyl dimethyl PABA and octyl methoxycinnamate in lipsticks

Abstract

The complex composition of lipstick formulations usually needs the use of organic solvents for sample dissolution. A treatment based on dissolution of cosmetic samples in ethanol-water (70 : 30, v/v) by use of ultrasonic irradiation is proposed. A C(18) stationary phase and an isocratic mobile phase of ethanol:water:acetic acid (70 : 29.5 : 0.5, v/v/v) with a flow rate of 1 mL min(-1) and an injection volume of 20 microL is proposed for the high-pressure liquid chromatography (HPLC) determination of four UV-filters, and detection was carried out at 309 nm. The limit of the chromatographic detection was 7.0 microg mL(-1) for butyl methoxydibenzoylmethane, 1.5 microg mL(-1) for benzophenone-3, 1.4 microg mL(-1) for octyl dimethyl p-aminobenzoic acid (octyl dimethyl PABA) and 2.7 microg mL(-1) for octyl methoxycinnamate. The relative standard deviations of the results were between 1.8 and 2.4%. The results were comparable to those obtained by a procedure based on the use of tetrahydrofuran. The method can be considered as a green analytical procedure because it only requires the use of small quantities of ethanol.