Abstract:

A high performance liquid chromatography method to determine six functional ingredients in whitening cosmetics was established for the simultaneous detection of α-arbutin, β-arbutin, deoxyarbutin, nicotinamide, hydroquinone and phenol in water-based, emulsion and cream cosmetics. For satisfactory sensitivity, stability and precision, the effects of detection wavelength, chromatographic column, mobile phase, extraction solvents, injection volume and column temperature were explored. Finally, the samples were extracted by 70% methanol solution, then the extract was separated on Waters HSS T3-C₁₈ （250×4.6 mm, 5 μm） column using methanol-water as the mobile phase with a flow rate of 1.0 mL/min, and qualitative and quantitative analysis was performed by high performance liquid chromatography with diode array detector at the detection wavelength of 220 nm. The results show that there are good linear relationships for 6 compounds in certain concentration range, with correlation coefficients （r²） larger than 0.999. The limits of detection （LOD） and limits of quantitation （LOQ） are in the range of 6-12 mg/kg and 20-40 mg/kg, respectively. The spiked recoveries for six compounds are in the range of 93.4%-109.6% with relative standard deviations （RSD） of 0.2%-3.8%. 150 batches of samples were determined. No deoxyarbutin, hydroquinone or phenol was detected. The content of nicotinamide, β-arbutin and α-arbutin range from 0.10% to 5.26%, 0.01% to 3.32% and 0.01% to 0.57%, respectively. The developed method is accurate, sensitive and simple for the determination of the six components in cosmetics. It is not only an effective method to detect deoxyarbutin in cosmetics, but also provides basis for simultaneous determination of these six components.

Key words: high performance liquid chromatography, whitening cosmetics, functional ingredient, arbutin, nicotinamide, hydroquinone, phenol