Application of multi-element time-resolved analysis to a rapid on-line matrix separation system for inductively coupled plasma mass spectrometry

Abstract

A rapid on-line matrix separation system for ICP-MS, using multi-element time-resolved analysis, was developed for the determination of several trace elements in complex matrix samples. A flow injection manifold was constructed consisting of a mini-column of 8-hydroxyquinoline covalently immobilized on to controlled pore glass. Analytes retained on the column were eluted using 0.1 ml of 2.0 mol l^–1 nitric acid. Sample volumes of 0.5 ml were analysed, yielding a preconcentration factor of 5 in addition to matrix separation. The system was optimized with respect to the variables of buffer concentration, buffer pH and eluent acid volume and concentration. Calibrations from both pure water and synthetic sea-water compared well and showed good linearity, with correlation coefficients of 0.988–0.999 for a range of analytes. The method showed good within-run reproducibility with precisions (s_r) at the 1 ng ml^–1 level of typically <3%. In general, recoveries between 89 and 104% were obtained, with the exception of Ni, which showed a recovery of 78% under the compromise conditions used. The method was validated by the analysis of estuarine (SLEW-1) and coastal (CASS-2) certified reference materials. Good agreement with the certified values was obtained for both of these materials.