Abstract: An analytical method to simultaneously determine 7 preservatives in soy sauce such as benzoic acid, sorbic acid, dehydroacetic acid and p-hydroxybenzoic acid esters (methyl paraben, ethyl paraben, propyl paraben and butyl paraben) was established using high performance liquid chromatography. The analytes were cleaned up on Oasis HLB column and detected at 230 nm and 260 nm. Their chromatographic separation was performed on Warters-C18 column (4.6 mm × 250 mm, 5μm) using acetonitrile and ammonium acetate as mobile phase for gradient elution. All the 7 preservatives displayed a linear concentration-peak area relationship over the concentration range of 0.4－100 mg/L, with a correlation coefficient of larger than 0.9994. The limits of detection of the method were from 0.28 to 0.55μg/mL. Average spike recovery rates for the 7 preservatives in a blank sample were from 84.4% to 102.3% (n = 3). This method can be used to detect preservatives in soy sauce rapidly and conveniently.

Key words: soy sauce, high performance liquid chromatography(HPLC), preservatives