[Simultaneous determination of 12 direct dyes in cosmetics by high performance liquid chromatography]

A method was developed for the simultaneous separation and determination of 12 direct dyes in cosmetics by high performance liquid chromatography (HPLC). The analytes were separated on an XB-C₁₈ column with acetonitrile-0.02 mol/L ammonium acetate aqueous solution (pH 9.0) as the mobile phases, and were detected using a diode array detector. The results indicated that the 12 direct dyes had good linearities with correlation coefficients greater than 0.999. The limits of detection were between 0.017 μ g/g and 1.7 μ g/g. The average recoveries ranged from 85.6% to 113.4%, and the relative standard deviations (RSDs) ranged from 1.0% to 7.7%. The intra-and inter-day RSDs were 0.4%-6.5% and 0.2%-7.5%, respectively. The method is simple, rapid, accurate, and is suitable for the determination of direct dyes in cosmetics.