Simultaneous Determination of Nine Banned Azo Dyes in Foodstuffs and Beverages by High-Performance Capillary Electrophoresis

A high-performance capillary electrophoresis (HPCE) method for simultaneous determination of nine banned azo dyes including orange 2 sodium salt, ponceau SX, ponceau 2R, metanil yellow, yellow 2G, ponceau 3R, naphthol orange, acid violet 7, and acid yellow 11 in foodstuffs and beverages was established. After being extracted with methanol and cleaned up with Proelut PWA column, the separation of the target azo dyes in sample solution was performed in an uncoated fused-silica capillary (60 cm × 75 μm I.D.) with an effective length of 50 cm. The running buffer consisted of 15 % acetonitrile-10-mM borate buffer (pH = 9.0), and the applied voltage was 25 kV with the separation temperature of 25 °C. The calibration curves of the method were linear in the range of 0.50–100.0 μg/ml with correlation coefficients greater than 0.999. The recoveries of the method ranged from 81.2 to 110 %. The limits of detection (LODs) and the quantification of the method were in the ranges of 25.1–75.1 μg/l and 0.083–0.25 mg/kg, respectively. The relative standard deviations (RSDs) of interday and intraday were in the ranges of 1.90 to 5.81 % and 0.12 to 3.42 %, respectively. This method has been successfully applied to the simultaneous determination of aforementioned nine azo dyes in foodstuffs and beverages.