Determination of Low Molecular Weight Carboxylic Acids in Water by HPLC with Conductivity Detection

Abstract

Low molecular weight carboxylic acids (C₂-C₈) were measured in aqueous samples using reverse phase HPLC coupled with conductivity detection. The aqueous samples are adjusted to pH 2 with H₂SO₄ and extracted with diethyl ether. The ether is allowed to evaporate over distilled water. The acid concentrate is analysed using a Zorbax-ODS column (25 mm × 4.6 mm). The method is simple, fast, and because of the selectivity of the conductivity detector, is relatively free from interferences. Average precision is estimated to be approximately ± 13% for the overall method.