Experimental design and capillary electrophoresis for simultaneous analysis of arbutin, kojic acid and hydroquinone in cosmetics

A statistical experimental design was used to optimize one micellar electrokinetic capillary electrophoresis (MEKC) for simultaneous analysis of arbutin (AR), kojic acid (KA) and hydroquinone (HQ). Untreated fused-silica capillaries were operated using a phosphate buffer (20 mM, pH 6.5) under 20 kV and detection at 200 nm. Quantitative linear ranges were 20–200 μg/ml for AR, 20–100 μg/ml for KA and 8–80 μg/ml for HQ with correlation coefficients ≥0.9994. R.S.D. and R.E. were less than 3.0% for the intra-day and inter-day analysis, and all recoveries were greater than 99%. Our method was applied to assay commercial cosmetics. The results were within the labeled amount of 99.6–102.5%.