Application of factorial design in optimization of nickel preconcentration by solid phase extraction and its determination in water and food samples by flame atomic absorption spectrometry

Abstract

A procedure for the preconcentration and determination of trace nickel in water and food samples using flame atomic absorption spectrometry (FAAS) is presented. It is based on column solid-phase extraction of nickel(II) ion by using Amberlyst 36 resin as a solid phase. The optimization step was carried out by using 2(3) full factorial design for the variables such as pH, flow rate and concentration of the analyte. In the established experimental conditions, nickel can be determined with a relative standard deviation of 1.8% for a nickel concentration of 100 mu g/L. Analytical detection limit was 0.86 mu g/L (N=20). The adsorption capacity of Amberlyst 36 is found to be 143 mg/g for nickel. The accuracy was confirmed by analysis of certified reference materials (tea leaves GBW 07605 and clay loam CMI 7003). The method was applied for nickel determination in real samples of tap water, waste water, dam water, carrot, parsley and lettuce.