Original Articles: 2010 Vol: 2 Issue: 2
Determination of Cr(III), Cu(II), Zn(II), Cd(II) and Pb(II) in food samples by FAAS after preconcentration on silica gel modified with 5-[2-hydroxybenzylideneamino]-2-hydroxy benzoic acid
Abstract
A method was developed for preconcentration of trace Cr(III),Cu(II),Zn(II),Cd(II) and Pb(II) prior to their determination by atomic absorption spectrometry. A new adsorbent 5-[2-hydroxy benzylideneamino]-2-hydroxy benzoic acid-immobilized silica gel was prepared as a new solidphase extractor. The recoveries of analytes at pH 4 with 100 mg solid phase were greater than 96% using 5 ml of 3N HNO3 eluent at a flow rate of 2 mi/min. The optimal experimental conditions for the absorption of analytes were investigated, including the effect of pH, the volume of sample, flow rate, elution condition and interfering- ions. The detection limits of the method were found to be 1.02, 4.2, 1.54 5.46, 2.1 µg. L–1 for Cr(III),Cu(II), Cd(II),Zn(II), Pb(II) respectively. The proposed method provides quantitative recoveries of target metal ions ranging from 96.0 to 99.3%. The method was successfully applied for the preconcentration of Cr(III), Cu(II), Zn (II), Cd (II) and Pb(II) in mango pulp, leafy vegetables and fish samples.