Determination of haloacetic acids in drinking water using suppressed micro-bore ion chromatography with solid phase extraction Original Research Article

Suppressed micro-bore ion chromatographic methods were developed for the analysis of monobromo- (MBAA), dibromo- (DBAA), monochloro- (MCAA), dichloro- (DCAA), trichloro- (TCAA), chlorodifluoro- (CDFAA) and trifluoroacetic acids (TFAA) in drinking water. Two methods were developed and optimised, one using a Dionex AS11HC (250 × 2 mm) column and the second using a Dionex AS16 (250 × 2 mm) column. Both methods employed electrolytically generated gradients of potassium hydroxide, combined with suppressed conductivity detection. Linearity, repeatability and limits of detection were determined for both methods. For trace determinations of haloacetic acids (HAAs) in real drinking water samples, combined preconcentration and matrix elimination was necessary and was investigated using solid phase extraction (SPE). Selectivity, percent recovery, capacity and reproducibility studies were carried out on LiChrolut EN cartridges. Under optimised conditions, average recoveries for MCAA, DCAA, TCAA, MBAA and CDFAA spiked in dinking water samples ranged from 62 to 88%, with an optimum preconcentration factor of 25. The reproducibility of recovery data for the above HAAs was found to range from 12 to 29% based upon six repeat recovery experiments. Excess residual levels of chloride and sulphate where reduced using Maxi-Clean IC-Ba and IC-Ag extraction cartridges. The optimised procedure was applied to drinking water samples and accuracy determined using standard addition. The combined SPE/IC method proved linear for MCAA, MBAA, DCAA, CDFAA, DBAA and TCAA (R2 ranging from 0.967 to >0.999, n = 4).