An environment-friendly procedure for the high performance liquid chromatography determination of benzoic acid and sorbic acid in soy sauce

A rapid, accurate and environment-friendly procedure has been developed for the HPLC-based determination of benzoic acid and sorbic acid contents in soy sauce. A C18 column served as the stationary phase, methanol-ammonium acetate buffer (0.02 M) (30:70, v/v) was used as the mobile phase, the flow rate was 1 mL/min, the UV detector was set at 225 nm and cinnamic acid was selected as an internal standard. Under such optimized conditions, benzoic acid, sorbic acid and the internal standard were separated within 8.1 min. This newly developed procedure also showed excellent recurrence, with a relative standard deviation of less than 3% and recoveries were 96.1-104.3%.