Ion chromatography by conductometric detection of some anions in rain and soil waters using silica based anion-exchange column and trimellitic acid eluent

Abstract

Anion chromatography with conductometric detection combining a silica based low capacity anion-exchange column and an aromatic tricarboxylic acid (trimellitic acid) of high eluting power was apphed to the determination of Cl, NO3 and SO42- in acid rain waters and their soil waters to elucidate the acidification mechanism of soil. When a 10 cm column and the 1.25 mM trimelhtic acid eluent at pH 4.65 were used to separate the 8 common anions (PO4-, Cl, NO2, NO3-, I-, SO42-, SCN- and 82O3-2), reasonable separation was obtained within 25 min. The calibration curves of the anions were linear up to at least 0.3 mM for monovalent and 0.2 mM for divalent anions. The detection hmits (S/N = 3) of major anions in rain water were 10 ng/ml for Cl, 25 ng/ml for NO3 and 28 ng/ml for SO42-. The method was successfully applied to the determination of anions in soil samples extracted by acid rain waters. The results showed that the amounts of SO42- adsorbed on the soil increased with increasing total anion concentration in the rain water and/or with decreasing pH of the rain water. © 1992, The Japan Society for Analytical Chemistry. All rights reserved.