Silica gel modified with diaminothiourea as selective solid-phase extractant for determination of Hg(II) in biological and natural water samples

Abstract

In this paper, a new method that utilizes diaminothiourea-modified silica gel as solid-phase extractant has been developed for preconcentration of trace Hg(II) prior to the measurement by cold-vapour atomic absorption spectrometry. The separation/preconcentration conditions of the analyte, which include the effects of the pH, sample flow rate and volume, elution conditions, shaking time, and interfering ions on the recovery of the analyte were investigated. At pH 2, the adsorption capacity of modified silica gel for Hg(II) was found to be 36.3 mg/g. According to the definition of IUPAC, the detection limits (3σ) of this method for Hg(II) was 0.28 ng/mL. The proposed method yielded satisfactory results when it was applied to the determination of trace Hg(II) in biological and natural water samples.

Keywords:

• Diaminothiourea
• Hg(II)
• Preconcentration
• CVAAS