Detection Of Glucocorticoids In Cosmetics

The paper established a practical, rapid, more sensitive method for simultaneous detecingsix glucocorticoids in cosmetics base on the microemulsion electrokinetic chromatography(MEEKC), which is using field amplified sample stacking (FASS) to enrich the sixglucocorticoids, The main contents are shown as follows:1. Experiment investigated the effects of surfactants, co-surfactant, oil phase and theconcentration and pH of the buffer on the separation of MEEKC, especially theβ-cyclodextrin was investigated. The results showed that β-cyclodextrin obvious impacted onthe degree of separation. Meanwhile, the electrophoresis conditions were studied. Through theoptimization of separation conditions, this method has higher separation selectivity thannormal MEEKC. Six substances can be baseline separated within16min, and eachcomponent has a good linear in the range of2.0~200mg/L, with the detection limits (S/N=3)between0.66~0.86mg/L. The method is suitable for the simultaneous analysis of sampleswith variety of glucocorticoids in cosmetics, but not for trace amounts of sample analysis.2. Microemulsion electrokinetic chromatography with field-amplified sample stackingfor analysis of six glucocorticoids in cosmetics was established, and glucocorticoid levels incosmetics were determined. The effects of some important factors were investigated, such assample matrix solution, water time and injection time. The optimum conditions were asfollows: sample were dissolved in borax-acetonitrile solution, water time was40s (P=16.0kPa), injection time was54s/-20kV, detection wavelength was240nm, temperature was25℃,separation voltage was-20kV. Samples were analyzed after pre-treated simply, and thelimits of detection were in the range of0.23~6.05μg/L. The maximum enrichment factor was94.0. The method can be applied to analysis of trace amounts of glucocorticoids.3. High performance liquid chromatography (HPLC) was further applied for analysis ofthese samples, using solid phase extraction techniques for purification and enrichment. Theestablished MEEKC-FASS method was statistical verificated. There were no significantdifferences between HPLC and MEEKC-FASS results by T-test which show that the accuracyof the method. The pre-treat for MEEKC-FASS was simple, and analysis time was shorter.Hence MEEKC-FASS has a greater advantage in the rapid analysis of glucocorticoids incosmetics.