RAPID IMMOBILISATION OF 8-HYDROXYQUINOLINE ONTO SILICA MATERIALS AND ITS APPLICATION FOR ON-LINE SOLID-PHASE EXTRACTION OF TRANSITION METALS FROM ENVIRONMENTAL SAMPLES BEFORE ICP-OES DETERMINATION

Chelating resins based on immobilised oxines are attractive solid-phase extraction (SPE) materials in the analysis of trace metals from environmental samples. The most common immobilisation procedure for bonding oxines to silica supports is time-consuming and incompatible with "green chemistry" regulations. In this work, a rapid, environmentally friendly chemical transformation to attach oxines (i.e. 8-hydroxyquinoline) to silica surfaces is reported. The chelating resin produced by the procedure described here maintains the chemical configuration (including the spacer arm separating the reactive groups from the matrix) and is identical to that obtained with the traditional method. The resin showed satisfactory capacity exchange and excellent performance as a SPE material for on-line sample preparation (preconcentration and matrix elimination) of some transition metals before their determination by ICP-OES. The applicability of this SPE material was tested by analysing Cu, Co, Zn, Ni and Pb in the range of 50-300 ng ml(-1) from a synthetic matrix simulating sediment. The recovery values ranged from 100% for Zn to 70% for Ni. The system was used with optimised parameters to analyse these ions in different sediment reference materials. The results showed good agreement with certified values.