Abstract:

A method for the simultaneous determination of 3 kinds of α-hydroxy acids and their esters in cosmetics, including gluconic acid, glucolactone and lactose acid, was developed by high performance liquid chromatography （HPLC）, and the results were confirmed by high performance liquid chromatography- tandem mass spectrometry （HPLC-MS/MS）. The above three substances were extracted ultrasonically with water. The analytes were separated on a Comixsil HCS （4.6 mm×150 mm, 3 µm） column by elution with 0.04 mol/L diammonium hydrogen phosphate- acetonitrile as mobile phase, and detected at the wavelengths of 214 nm. Quantification analysis was performed by the external standard method. HPLC-MS/MS was used for gradient elution with 0.1% formic acid- acetonitrile containing 0.1% formic acid as mobile phase. The analytes were separated on a Waters T3-C18 （2.1 mm×100 mm, 1.8 µm） column. Qualitative analysis was performed by electronic spray ionization under a negative ion mode with multiple reaction monitoring （MRM）. The results indicate that gluconic acid and lactose acid show good linearity in its own concentration range with the correlation coefficient of R²>0.999. The detection limits of gluconic acid and glucolactone are 100 μg/g, and that of lactose acid is 500 μg/g. The average spiked recoveries of these three compounds in 4 cosmetic matrices are all in the range of 90.8%-110.1%, with the RSDs of 0.3%-4.4%. The results indicate that the method is simple, sensitive and accurate, and is suitable for the determination of 3 kinds of α-hydroxy acids and their esters in cosmetics.

Key words: cosmetics, gluconic acid, glucolactone, lactose acid, HPLC, HPLC-MS/MS