Objective To establish an analytical method for the determination of resorcinol, ferulic acid, phenethylresorcinol and benzoyl peroxide in freckle whitening cosmetics by high performance liquid chromatography (HPLC), to provide data support for the establishment of cosmetics inspection methods and technical support for the supervision of the cosmetics industry.

Methods The analytes in samples were extracted by ultrasonic acetonitrile after methanol vortex, and then filtered by centrifugation and microporous filter membrane. Finally, the analytes were separated with a SVEA C4 column (250 mm×4.6 mm, 5 μm). The mobile phase was composed of 0.1% phosphoric acid solution -acetonitrile, and the gradient elution was applied, with a flow rate of 1.0 mL·min^-1. The samples were detected by an ultra-violet detector and quantified by external standard method.

Results Resorcinol, ferulic acid, phenylethylresorcinol and benzoyl peroxide showed good linearity in the experimental range with r>0.999. HPLC was used to investigate the positive spiked recoveries of ferulic acid or phenylethylresorcinol with different matrices. The results showed that the recoveries were all in the range of 87.48% to 101.00%, and the relative standard deviations were all in the range of 3.4% to 4.1%. Furthermore, HPLC also examined the blank matrix spiked with the recoveries ranged from 93.26% to 107.66%, with the relative standard deviation of 0.90% to 2.90%. The limits of detection ranged from 0.000 8% to 0.002%. Among the 30 batches of standard freckle whitening cosmetics determined, 6 batches of which were detected with phenethylresorcinol and 1 batch with ferulic acid.

Conclusion HPLC is a method with rapidity, simplicity, and high sensitivity, which is suitable for the simultaneous determination of resorcinol, ferulic acid, phenethylresorcinol and benzoyl peroxide in commercially available cosmetics.