Résumé
Objective: The method for separation by capillary zone electrophoresis (CZE) and electrochemical determination of organic acids in fruit juices was developed. Method: In this system, 0.2mmol/L cetylpyridinium bromide (CPB) was used as an electro osmotic flow (EOF) modifier to reverse the direction of EOF. cyclodexfrin ( -CD) was added into running buffer to improve the separation efficiency. Then, the optimal separation conditions were achieved and successfully employed to separate six organic acids, including oxalic, malic, tartaric, succinic, fumaric acid and citric acids. One nano palladium modified carbon paste electrode was used for determination. Results: The calibration curves for all organic acids studied were linear with 2-3 orders (1 10–6-1.0 10–3 mol/L) of magnitude and all the detection limits (S/N=3) were below 2 mol/L. The RSD was between 1.05%-2.15% , and recovery was 93.4% . Conclusion: CZE separation combined with electrochemical detection is suitable for simultaneous determination of organic acids in fruit juices quickly with high sensitivity and selectivity.