Preconcentration of lead(II) in environmental waters using a chelating resin and subsequent determination as a resin–water suspension by hydride generation atomic absorption spectrometry

Abstract

A method is described for the determination of lead(II) in environmental water samples by hydride generation atomic absorption spectrometry combined with a resin–water suspension sampling technique after preconcentration using a chelate-forming resin. The chelate-forming resin was prepared by the modification of a commercially available anion-exchange resin and the sodium salt of a sulfonic acid derivative of dithizone, disodium (4-sulfophenyl)-1-[2-(4-sulfophenyl)hydrazide]diazenecarbothioate (DzS). Lead(II) was found to be collected completely in the pH range between 6.3 and 10 by the DzS-loaded resin. When the aqueous suspension of metal-adsorbed resin was introduced into a hydride generation system with 1 mol l^–1 HCl, 15% v/v H₂O₂ and 5% m/v NaBH₄(in 0.5% m/v NaOH), lead(II) in the resin was converted into its hydride effectively. Neither DzS nor DzS-loaded resin interferes with the generation of lead hydride. The recovery and relative standard deviation were found to be 104 and 4%(n=4), respectively, when 2.5 µg of lead(II) was spiked into 1 l of distilled water. The proposed method was applied to the determination of trace amounts of lead(II) in environmental water samples.