Determination of Sorbic Acid and Benzoic Acid in Wine by Ion Chromatography

Ion chromatography was applied to the rapid determination of sorbic acid and benzoic acid in wine. The sample was diluted 20 times with ultrapure water, and the pigment in the solution was adsorbed and extracted with polyamide powder. The purified solution was separated on an IonPac AS11-HC anion chromatographic column with 30 mmol·L-1 KOH solution as eluent. The analytes were detected by suppressed conductivity detector. External standard method was used for quantification. Linear relationship were found between the values of peak areas and the mass concentration of both sorbic acid and benzoic acid in the same range of 0.5-50 mg·L-1, with detection limits (3S/N) in the range of 1.4-1.7 mg·L-1. Values of recovery rates obtained by standard addition method were in the range of 97.7%-104% and RSDs (n=6) were in the range of 2.4%-3.4%.