Solid Phase Extraction of Trace Elements in Water and Tissue Samples on a Mini Column with Diphenylcarbazone Impregnated Nano-TiO2 and Their Determination by Inductively Coupled Plasma Optical Emission Spectrometry

This study presents a simple, robust, and environmentally friendly solid phase extraction procedure for multi-element determination by inductively coupled plasma optical emission spectrometry (ICP-OES) using diphenylcarbazone (DPC) impregnated TiO2 nanopowder (n-TiO2). DPC was successfully impregnated onto n- TiO2 in a colloidal solution. A number of elements, including Co(II), Cr(III), Cu(II), Fe(III), Mn(II), and Zn(II) were quantitatively preconcentrated from aqueous solutions between pH 8 and 8.5 at a flow rate of 2mL min (-)1, and then eluted with 2 mL of 5% HNO3 (v/v). A mini-column packed with 0.12 g DPC impregnated n- TiO2 retained all elements quantitatively from an up to 250 mL multi-element solution (2.5 mu g per analyte) affording an enrichment factor of 125. The limits of detection for the preconcentration of 50 mL blank solutions (n = 12) were 0.28, 0.15, 0.25, 0.22, 0.12, and 0.10 mu g L (1) for Co, Cr, Cu, Fe, Mn, and Zn, respectively. The relative standard deviation for five replicate determinations was 0.8, 3.4, 2.6, 2.2, 1.2, and 3.3% for Co, Cr, Cu, Fe, Mn, and Zn, respectively, at a 5 mu g L-1 level. The method was validated with analysis of freshwater and lobster hepatopancreas certified reference materials, and then applied to the determination of the elements from tap water and lake water samples by ICP-OES.