Separation and determination of organic acids in foods by capillary electrophoresis with indirect UV detection

Capillary electrophoresis(CE) with indirect UV detection method for the separation and determination of several organic acids commonly found in foods were developed. Effects of pH, background electrolytes and electroosmotic flow modifiers on separation were investigated. The carrier electrolyte pH played an important role in the separation of organic acids. All analytes could be separated in one run by performing CE with 5.0 mmol/L phthalate-3.0 mmol/L dodecyl trimethyl ammonium chloride (DTAC) at pH=7.0 within 6 min. The reproducibility (RSD) of the method is less than 0.17% for migration time and 4.2% for the peak area (n=8). Linearity was observed more than one order between 1 and 80 mg/L. The detection limits are obtained from 0.5 to 5.0 mg/L. A variety of matrix samples such as wine, juices and soy sauce were determined by the method. The recoveries were in the range of 95%similar to 102%.