Application of Improved Micellar Electrokinetic Capillary Chromatographic and Liquid Chromatographic Method for Determination of Dehydroacetic Acid in Six Species Key Foods

The electrophoretic, chromatographic and sample pretreatment conditions for the previously established micellar electrokinetic capillary chromatographic method (MEKC) in our laboratory and the liquid chromatographic (LC) method of the national standard were improved for the analysis of dehydroacetic acid (DHA). DHA in six species key foods could be accurately assayed by both of the two improved MEKC and LC methods. The analytical results could provide a basis for reassessing the risk of DHA and revising or resetting the permitted levels of DHA in six species key foods. The limits of detection and quantitation for the improved MEKC and LC method were 0.2, 0.5 mg/L and 0.05, 0.2 mg/L, respectively. The recoveries of the spiked blank samples of the six species key foods were in the ranges of 81.9%~116.0% with relative standard deviations ranging from 0.4% to 7.3%. 284 food samples were analyzed by the improved MEKC method. None of them exceeds the permitted levels. Forty-five samples were determined simultaneously by the two improved methods. The results of 20 positive samples were compared which were in agreement with each other. Both improved LC and MEKC methods have the advantages of simple sample pretreatment, which is suitable for routine analysis.