Determination of Synthetic Colors in Soft Drinks and Confectioneries by Micellar Electrokinetic Capillary Chromatography

A method of micellar electrokinetic capillary chromatography (MEKC) was developed for simultaneous determination of 14 synthetic colors in soft drinks and confectioneries. The optimal solvent of MEKC method for separating all colors was a mixed solution comprised of 18% acetonitrile and 82% 0.05 M sodium deoxycholate in borate-phosphate buffer (pH 7.8). These colors were well separated within 20 min using 57 cm × 75 micrometer uncoated fused-silica capillary column, operating at 25 kV and detected by UV at 214 nm. The average recovery of all colors spiked into soft drinks and confectionery was better than 82%. The addition of illegal colors was not found after testing 30 samples. In retail foods, the colorant found in highest concentration was tartrazine (155 μLgg/g sample).