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 aci d, formic acid, acetic acid, propionic acid, and butyric acid in envir onmental microcosm samples using ion-exclusion chromatography. The chr omatographic 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 inv estigated. Methods for carbonate removal were also examined. Sub mg/L detection limits and small analytical variations (less than 1%) were o btained with all five acids. Calibration curves with regression coeffi cients (r(2)) 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 carboxyl ic acids was less than 20 min with a relatively small sample volume re quirement (similar to 0.5 ml). The recoveries of the acids from microc osm samples were between 80 to 102%.