Abstract: A method for the determination of four kinds of preservatives (dehydroacetic acid,chlorphenesin,phenyl 4-hydroxybenzoate and benzyl 4-hydroxybenzoate) in cosmetics by high performance liquid chromatography (HPLC) was established.A Diamonsil C₁₈ column (250 mm×4.6 mm,5 μm) was used with methanol-0.1% formic acid solution as the mobile phase under the condition of gradient elution.Samples were extracted with methanol-water solution with assistance of ultrasonic wave for 30 min,and the samples were detected by VWD detector.Results show that the four kinds of preservatives are baseline separated in12.5 min.All correlation coefficients (r) are more than 0.998,with the average recoveries range from 88.5% to 102.7%.The intra-day precision (RSD) values are below 3.1% and inter-day precision (RSD) values are below 3.7%.

Key words: cosmetics, high performance liquid chromatography, preservative