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 $\mu $g L$^{-1}$ for Pb and 1.1 $\mu $g L$^{-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.

Keywords: Solid phase extraction, N,N'-bis(4-methoxysalicylidene)-1,3-propanediamine, modified silica gel, lead, zinc, FAAS

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