Miniaturisation of a matrix separation/preconcentration procedure for inductively coupled plasma mass spectrometry using 8-hydroxyquinoline immobilised on a microporous silica frit

Abstract

A comparison has been performed on miniaturised matrix separation/preconcentration procedures using packed micro-columns of imminodiacetate (IDA) chelating reagents and an 8-hydroxyquinoline (8-HQ) micro-column. Commercially available IDA reagents, Prosep and Muromac, were packed into micro-columns and 8-HQ has been immobilised on a novel microporous silica structure. These have been successfully utilised for the determination of several trace elements in complex matrix samples. The miniaturised matrix separation/preconcentration procedures have been developed to reduce sample analysis time. A microconcentric nebuliser in the ICP-MS permits the multielement analysis on a smaller volume of solution leading to a reduction in reagent consumption and a more efficient procedure. Preparation of the micro-columns is described along with optimisation of the procedures with respect to the variables buffer concentration, buffer pH, eluent acid concentration and reagent flow rates. Sample analysis times are compared for both miniaturised systems. Analysis times of 3.0 min for the IDA column and 2.3 min for the 8-HQ column are reported. Calibrations showed good linearity with correlation coefficients of 0.999–0.9998 for IDA columns and 0.999–0.9997 for 8-HQ column for a range of analytes. Recoveries ranging from 91–102% for IDA columns and 96–105% for the 8-HQ column are reported for a range of elements. The method was validated by the analysis of estuarine (SLEW-1) and coastal (CASS-2) certified reference materials. Good agreement between the certified and reference values was obtained for the materials.