Preparation of Silica-4-(2-pyridylazo) resorcinol chelator for solid phase extraction of transition metals from groundwater

The determination of trace heavy metals in environmental samples requires reliable sample preparation method to improve instrument detectability or minimize matrices effect. Solid phase extraction (SPE) using metal chelators is an attractive approach for the selective extraction of trace metals from aqueous media in various applications. In this work, chelating resin was prepared by chemical attachment of the chelating moiety, 4-(2-pyridylazo)resorcinol(PAR) onto silica gel using an eco-friendly chemical transformation. The successfulness of the chemical modification was confirmed by Fourier transform infrared (FTIR), elemental analysis (EA) and scanning electron microscopy (SEM). The separation/preconcentration conditions of analytes including exchange capacity, effect of pH, adsorption kinetics and isotherm for metal extraction, were investigated.At optimum conditions, the resin loading capacity for the metals Cu/sup 2+/, Ni/sup 2+/ and Mn/sup 2+/were 0.121, 0.132 and 0.124 mmolg-1in that order. The material performance as SPE sorbent for trace metals has been assessed using Cu/sup 2+/, Ni/sup 2+/ and Mn2+ in certified reference natural water sample, and real groundwater samples from Almedinah AlMunawarah. The accurate and precise results verify the resin appropriateness for matrix removal/ preconcentration prior to the analysis of heavy metals from this type of matrices. (author)