Application of nanometer zirconium oxide immobilized on silica gel as a solid phase extraction sorbent for the preconcentration of Pb in water samples prior to flame atomic absorption spectrometry determination

摘要

A new method has been developed for the determination of Pb(II) based on the separation and preconcentration with a micro-column packed with nanometer ZrO_2, immobilized on silica gel (ZrO_2/SiO_2) prior to its determination by flame atomic absorption spectrometry. The optimum experimental parameters for preconcentration of Pb(II), such as pH, sample flow rate and volume, eluent and interfering ions, were investigated. Lead was quantitatively retained by ZrO_2/SiO_2 in the pH range of 4-6, then eluted completely with 0.5 mol L-1 HNO_3. The adsorption capacity for Pb(II) was 4.79 mg g~(-1). The detection limit for Pb(II) was 5.2 μg L~(-1) with an enrichment factor of 100. The relative standard deviation was 2.5% (n = 7, c = 1.0 μg mL~(-1)). The method was applied to the determination of trace amounts of Pb(II) in real samples with satisfactory results.