Determination of Benzoic Acid, Chlorobenzoic Acids and Chlorendic Acid in Water

Abstract The title compounds were isolated from acidified (pH 1) water by extraction with methyl t-butyl ether. Analytes were concentrated by back-extracting the ether with 0.1 N sodium hydroxide which was separated and acidified. This solution was analyzed by C18 reversed-phase HPLC with water/acetonitrile/ acetic acid eluent and UV detection at 222 nm. The method has detection limits of 200 μg/L for chlorendic acid and 100μg/L for benzoic acid and each isomer of chlorobenzoic acid. Validation studies with water which was fortified with the analytes at concentrations ranging from one to ten times detection limits resulted in average recoveries of >95%.