微乳毛细管电动色谱快速分析脂溶性维生素

Rapid Determination of Fat-soluble Vitamins with Microemulsion Capillary Electrokinetic Chromatography

建立了一种新的微乳体系,成功地应用于微乳毛细管电动色谱(MEEKC)快速分析脂溶性维生素VA、VD3和VE。本微乳液的组成为:1.2%(m/m)十二烷基硫酸钠(SDS)-21%(V/V)正丁醇-18%(V/V)乙腈-0.8%(m/m)正己烷-20mmol/LH3BO3-Na2B4O7缓冲液(pH8.4)。该微乳体系中,助表面活性剂正丁醇和有机溶剂乙腈对脂溶性维生素的分离起到了重要的作用。当分离电压为25kV,柱温为25℃时,VA、VD3和VE在13min内达到基线分离。3种脂溶性维生素的迁移时间和峰面积的RSD(n=5)<2.5%和4.5%;VA、VD3和VE分别在20～1000、5～1000和5～1000mg/L范围内与峰面积呈线性关系;检出限(S/N=3)分别为12、0.72和0.29mg/L。本体系应用于市售VE胶囊的测定,结果与标示值相符。

A novel system was developed for the rapid determination of fat-soluble vitamin A, D3 , and E with microemulsion electrokinetic chromatography （MEEKC）. The microemulsion consists of 1.2% （w/w） sodium lauryl sulphate （SDS）, 21% （V/V） 1-butanol, 18% （V/V） acetonitrile, 0. 8% （w/w） n-hexane, 20 mmol/L borax buffer （ pH 8.4）. 1-Butanol as the cosurfactant and acetonitrile as the organic solvent mod- ifier in MEEKC running buffer played an important role for separation of three fat-soluble vitamins. The three analytes were baseline separated within 13 min at 25 kV and 25 ℃. The RSD values（n = 5）of migration time and peak areas of the analytes were less than 2.5% and 4.5% , respectively. Good linear relations between peak areas and concentration of analytes were established in the range of 20 - 1000 mg/L for vitamin A, 5 - 1000 mg/L for vitamin D3 , and 5 - 1000 mg/L for vitamin E. the detection limits （S/N =3） were 12,0.72 and 0. 29 mg/L, respectively. This method has been successfully applied for the analysis of commercial vitamin E capsules, the determination results were accorded with the declared in the label.