Determination of bromide, bromate and other anions with ion chromatography and an inductively coupled plasma mass spectrometer as element-specific detector

Abstract

An implementation of the Dionex IonPac AS12A analytical column with an element-specific ICP-MS detection is described for the simultaneous determination of halogen and oxyhalogen anions, sulfate, phosphate, selenite, selenate and arsenate. The chromatographic separation was achieved in less than 4 min with an aqueous 11 m M (NH 4) 2CO 3 (pH 11.2, adjusted with aqueous ammonia) as eluent. Special emphasis was given to optimize the ICP-MS detection conditions for the reliable detection (RSD<5%) of bromate and bromide at a bromine concentration level of 1.0 μg l −1 with 50 μl sample injection volume. In order to achieve the highest detector response for bromine species an ultrasonic nebulizer equipped with a membrane desolvator had to be employed. The detection limits ( S/ N=3, sample injection volume 50 μl) obtained with the IC–ICP-MS after the optimization were 0.67 μg l −1 for BrO 3 −, 0.47 μg l −1 for Br −, 69 μg l −1 for ClO 2 −, 4 μg l −1 for Cl −, 47 μg l −1 for ClO 3 −, 13 μg l −1 for SO 4 2−, 36 μg l −1 for PO 4 3−, 0.4 μg l −1 for SeO 3 2−, 0.3 μg l −1 for SeO 4 2−, and 0.4 μg l −1 for AsO 4 3−.