HPLC Determination of 6 Additives of Limited Quantities in Cosmetics with Dispersive Extraction

Six substances of limited quantities, i.e., preservatives and anti-oxidant in cosmetics were extracted by dispersive extraction with acetonitrile-acetone (50+50) mixture as solvent and wheat bran powder as dispersant. The extract was used for HPLC analysis, with DAD for detection. Inertsil ODS-sp C18 column (4.6 mm×250 mm, 5 μm) was used as stationary phase and mixtures of methanol and ammonium acetate solution of pH 3.5 with different mixing ratio were used as mobile phase in the gradient elution. Under the optimized conditions, linear relationships between values of peak area and mass concentration of the 6 compounds were kept in the same range of 0.20-100 mg·L-1, with detection limits (3S/N)in the range of 0.004-0.015 mg·kg-1. Values of recovery found by standard addition method were in the range of 85.4%-113% with RSD′s (n=5) in the range of 1.1%-6.9%.