Validated reversed phase HPLC method for the analysis of the food additive, sodium benzoate, in soft drinks and jams

A rapid, simple, and sensitive method is described for the determination of the food preservative sodium benzoate in soft drinks, various jams, and ketchup. The method utilizes high performance liquid chromatography followed by diode array detection. Chromatographic separation was achieved using a C-18 reversed phase column and methanol: water (70:30, v/v) adjusted to pH 3.45 with glacial acetic acid as mobile phase, 0.45 mL. min(-1) flow rate, and UV detection at 245 nm. Amoxicillin was used as the internal standard. The retention time observed for sodium benzoate and amoxicillin were 5.01 and 12.07 min, respectively. The method is selective, reliable, and reproducible with a relative standard deviation of 0.66 and linear in the range of 50-450 ng/ML sodium benzoate concentration. The limit of detection and limit of quantification concentrations were 61 pg/mL and 203 pg/mL, respectively. The proposed method can be used for the routine analysis of sodium benzoate in soft drinks and jams.