Simultaneous preconcentration of cd(II) and pb(II) with n,n '-bis(4-methoxysalicylidene) ethylenediamine coated silica gel prior to determination by flame atomic absorption spectrometry

Abstract

In this paper, a silica gel-based new sorbent was prepared with a Schiff base, called as N,N'-bis(4-methoxysalicylidene) ethylenediamine (MSE). The modified silica gel (Si-MSE) was used for simultaneous separation and preconcentration of Cd(II) and Pb(II) from aqueous solutions. Determination of analyte concentrations in eluates were achieved by flame atomic absorption spectrometry (FAAS). The analytical variables including pH, flow rate, and sample volume for sorption and flow rate, eluent concentration, and eluent volume for elution, were optimized by central composite design (CCD). HNO3 was used as eluent and maximum preconcentration factor was found to be 200. Limit of detections (LODs) were found to be 49.6 ng L-1 and 1.3 mu g L-1 for Cd(II) and Pb(II), respectively. Validation of the developed method was performed by using certified reference material (TMDA-53.3) and mixed metal standard. The methodology was applied for determination of Cd(II) and Pb(II) in natural water samples and satisfactory results were obtained.