Ion-exclusion chromatographic determination of carboxylic acids used to support the microbially mediated reductive dechlorination of tetrachloroethene

An analytical method was developed for the determination of lactic acid, formic acid, acetic acid, propionic acid, and butyric acid in environmental microcosm samples using ion‐exclusion chromatography. The chromatographic behavior of various eluents was studied to determine the optimum analytical conditions for eluent concentration and flow rate. Matrix effects caused by inorganic anions including carbonate were investigated. Methods for carbonate removal were also examined. Sub mg/L detection limits and small analytical variations (less than 1%) were obtained with all five acids. Calibration curves with regression coefficients (r2) of 0.998 to 1.000 were obtained for acid concentrations ranging from 2.00 to 200.00 mg/L. The total run time for five carboxylic acids was less than 20 min with a relatively small sample volume requirement (∼0.5 ml). The recoveries of the acids from microcosm samples were between 80 to 102%.