| A micellar electrokinetic capillary chromatographic(MEKC) method was developed for the separation and determination of 13 artificially synthesized pigments,including ten water-soluble and three fat soluble substances(e.g.auramine O,Sudan Ⅱ,Sudan Ⅰ,Sudan Ⅲ&Ⅳ,acid orange,brilliant,acid red 92,erythrosine,uranine,allura red,acid red 1,indigo and sunset yellow) in food.The parameters including buffer composition,pH value,concentration of boric acid and SDS were optimized by orthogonal experiment method.At the same time,effects of organic modifier,separation voltage and temperature on the separation were investigated.The optimal conditions were as follows:separation column:a 75 μm×58.5 cm uncoated fused silica capillary;buffer:40 mmol/L sodium borate(pH 9.5);BGE solution:20 mmol/L SDS-30% acetonitrile;detection wavelength:220 nm,run voltage:25 kV;temperature:25 ℃,and the sample was injected at 50 MPa for 5 s.Under the optimal conditions,the linear relationship between concentration and peak area for each of these analytes was obtained in the concentration range of 3-200 mg/L,with correlation coefficients larger than 0.99.The method was applied in the determination of 13 artificially synthesized pigments in samples of spiced duck wings,dried bean milk cream in tight rolls,ketchup and chili powder,with recoveries between 98% and 104%.The limits of detection ranged from 3.0 mg/L to 16.0 mg/L.The results indicated that the method was simple and accurate,and was suitable for the simultaneous determination of the thirteen pigments in food samples． |