Schiff base immobilized silica gel framework as an efficient sorbent for preconcentration of Pb and Zn ions in aqueous media

Abstract

A novel preconcentration method for Pb and Zn ions using a column packed with Schiff base modified silica gel is described. The method was based on the sorption of analytes on N,N'-bis(4-methoxysalicylidene)-1,3-propanediamine modified silica gel and elution with HNO 3 prior to flame atomic absorption analysis. The parameters pH, flow rate, sample volume, eluent volume, and concentration were optimized using a central composite design. The detection limits were 10.0 µ g L −1 for Pb and 1.1 µ g L −1 for Zn. The suggested procedure was validated with Lake Ontario water as a certified reference material and recovery percentages were 101.8% for Pb and 98.2% for Zn. The application of the method was performed on snow, tap, bottled, mineral, and lake water samples and recovery percentages were in the range of 96.7%-101.6% and 96.4%-98.4% for Pb(II) and Zn(II), respectively.