In the presented work, a-benzoin oxime immobilized SP70 chelating resin was synthesized for separation and preconcentration of Pb(II), Cd(II), Co(II) and Cr(III). The optimization procedure for analytical parameters including pH, eluent type, flow rate, etc. was examined in order to gain quantitative recoveries of analyte ions. The effects of foreign ions on the recoveries of studied metal ions were also investigated. The detection limits Q(T) were found to be 16.0, 4.2, 1.3, 2.4 mu g L-1 for Pb, Cd, Co and Cr, respectively. The preconcentration factor was 75 for Ph, 100 for Cd, Co and Cr. The optimized method was validated with certified reference materials and successfully applied to the waters, crops and pharmaceutical samples with good results (recoveries greater than 95%, R.S.D. lower than 10%). (c) 2006 Elsevier B.V. All rights reserved.