Simultaneous Determination of Organic Acids in Commercial Vinegar by Photometric Ion Chromatography

A simultaneous determination method for five organic acids in vinegar has been established by photometric ion chromatography. Both trace components (lactic, gluconic, succinic and pyroglutamic acids) and the major component (acetic acid) in vinegar were separated on a TSK gel IC-Anion-PW column with 0.45 mM o-aminobenzenesulfonic acid aqueous solution as an eluent. Their elutions were detected as positive peaks before the system peak, and a negative peak after that by a UV monitor. The sensitivities of trace components were enhanced by adjusting their elutions close to the system peak. The lowest detection limits were 10μM lactic acid, 5μM gluconic and succinic acids and 3μM pyroglutamic acid, respectively. The only pretreatment necessary was dilution of vinegar 100-fold with the eluent. The results obtained by the proposed method were in good agreement with those by the enzymatic one