大体积进样-非匀强电场扫集微乳毛细管电动色谱法测定化妆品中糖皮质激素

Online Determination of Glucocorticoids in Cosmetics by Large Volume Sample Injection- Reduced Electric Field Sweeping and Microemulsion Electrokinetic Chromatography

建立了一个简单有效的微乳毛细管电动色谱（MEEKC）在线富集-大体积进样（LVSI）与非匀强电场扫集（REFS）联用测定化妆品中4种糖皮质激素（泼尼松、氢化可的松、泼尼松龙和倍他米松）的方法。MEEKC的缓冲体系组成为：2.4%SDS,0.6%正辛烷,6.6%正丁醇,30 mmol/L硼酸盐缓冲液（pH 8.2）,分离电压为9.6 kV,进样压力为12.3 kPa,进样时间为95 s,检测波长为230 nm。在最优实验条件下,4种糖皮质激素的富集倍数为853~933倍,在0.015~14 mg/L范围内呈线性关系,检出限（S/N=3）为4~8μg/L。应用此方法分析了化妆品样品,回收率为93.7%~103.8%,相对标准偏差（n=5）均不大于4.4%。

A simple and efficient online sample pre-concentration method composed of large volume sample injection（ LVSI）- reduced electric field sweeping（ REFS） and microemulsion electrokinetic chromatography（ MEEKC） was developed for the determination of glucocorticoids（ prednisone,hydrocortisone,prednisolone and betamethasone） in cosmetics. The microemulsion background buffer was composed of 2. 4% dodecyl sodium sulfate,6. 6% butanol,0. 6% octane and 30 mmol / L borate buffer（ pH 8. 2）. The separation voltage was 9. 6 kV and the sample was injected at 12. 3 kPa for 95 s.The detection wavelength was set at 230 nm. Under the optimum conditions,the enrichment factors ranged from 853 to 933. The calibration curves were linear in the concentration of 0. 015- 14 mg / L.The limits of detection（ S / N = 3） were in the range of 4- 8 μg / L. The developed method was used to analyze corticosteroids in cosmetics with recoveries of 93. 7%- 103. 8% and RSDs（ n = 5） not more than 4. 4%.