Simultaneous determination of l-ascorbic acid, ascorbic acid-2-phosphate magnesium salt, and ascorbic acid-6-palmitate in commercial cosmetics by ... [An article from: Analytica Chimica Acta]

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Description:
l-Ascorbic acid (LAA) can be used as a whitening agent in cosmetics. Because of its instability, some more stable derivatives have been developed to control melanin production, such as ascorbic acid-2-phosphate magnesium salt (AAPM) and ascorbic acid-6-palmitate (AA6P). To assess the quality of cosmetics, a micellar electrokinetic capillary electrophoresis technique (MEKC) was established for simultaneous analysis of AA and its two derivatives. Separation was performed with 10mM borate (pH 9.5) containing 50mM sodium dodecyl sulfate (SDS) at 20kV. The detection wavelength was 265nm. Several parameters, including borate concentration, buffer pH, and SDS level, were investigated. On method validation, calibration curves were linear over a concentration range of 150.0-1000.0@mM for LAA and 200.0-1000.0@mM for AAPM and AA6P. For intraday and interday analysis, relative standard deviation and relative errors were all less than 3%. Limits of detection were 70@mM for AAPM and AA6P, and 50@mM for LAA. All recoveries were greater than 95%. This method was applied to quality control of commercial cosmetics.