Abstract:

A new micellar electrokinetic capillary chromatographic method for the simultaneous determination of phenol, hydroquinone, arbutin and kojic acid in whitening cosmetics was developed. The selection and optimization of separation buffer were investigated in detail. The four substances were separated and determined within 5 minutes using uncoated fused silica capillary with an internal diameter of 50 μm and a total length of 40.2 cm （effective length of 30 cm） as separation column and 110 mmol/L H₃BO₃, 5 mmol/L Na₂HPO₄ （pH=7.5） and 120 mmol/L sodium dodecyl sulfate （SDS） as separation buffer solution. The detection wavelength was 214 nm. The results show that the corrected peak area （A_c） and the concentrations of the four components have good linear relationships within the ranges of 12.5-2 000 μg/g with the linear correlation coefficients （r） all above 0.999. The recoveries at three spiked levels are in the ranges of 96%-112%, and the relative standard deviations are in the ranges of 0.08%-2.50%. The limits of detection are in the ranges of 2.5-12.5 μg/g. The newly established method is suitable for actual sample analysis with high accuracy, good repeatability and simplicity.

Key words: cosmetics, micellar electrokinetic capillary chromatography, arbutin, hydroquinone, kojic acid, phenol