Differential Determination of Organic Mercury, Mercury(II) Oxide and Mercury(II) Sulfide in Sediments by Cold Vapor Atomic Absorption Spectrometry

Abstract

A method has been proposed for the differential determination of mercury compounds in sediments, based on their successive extraction followed by a cold vapor atomic absorption spectrometric (CVAAS) determination.Organic mercury was first extracted by shaking a sediment sample with chloroform. The mercury in the extract was subsequently back-extracted into a 0.01 M sodium thiosulfate solution. In order to separate mercury(II) oxide from mercury(II) sulfide, the residue was treated with 0.05 M sulfuric acid so as to extract only mercury(II) oxide. Mercury(II) sulfide was finally extracted from the residue with 1 M hydrochloric acid containing 3% sodium chloride in the presence of copper(I) chloride. The mercury in each extract was determined by CVAAS. When artificial standard sediment samples spiked with a given amount of each mercury compound were successively treated by the above-mentioned procedures, the recoveries of organic mercury, mercury(II) oxide and mercury(II) sulfide were 99.9, 99.5 and 98.2%, respectively. This method was successfully applied to a differential determination of mercury compounds in marine sediments.

Mercury speciation in sediments at a municipal sewage sludge marine disposal site

“…MeHg was extracted from the sediment or the ASS as a halide salt with dichloromethane, followed by a cleanup procedure involving the formation of a water-soluble adduct, its extraction into an aqueous phase which was separated and oxidized by BrCl for Hg measurement (Cai et al, 1997;Longbottom et al, 1973;Sakamoto et al, 1992). At the early stages of this work both MeHg and Ethyl Hg were measured by HPLC after solvent extraction (Cai et al, 1997;Hintelmann and Wilken, 1993;PS Analytical, application 10.025, 2001;Wu, 1991).…”

Characterization and speciation of mercury-bearing mine wastes using X-ray absorption spectroscopy

“…Other methods, such Ž as sequential chemical extractions Revis et al, . 1989;Sakamoto et al, 1992 and thermal desorp-Ž tion Azzaria and Aftabi, 1991;Biester and Scholz, . 1997 , have been used to indirectly determine the speciation of mercury by measuring extractable fractions of mercury and equating them to unique mercury species.…”

Non-chromatographic atomic spectrometric methods in speciation analysis: A review

“…Furthermore, Pd-DDC was used as modifier for both Hg and methylmercury determinations [31]. For Hg speciation in sediments, Sakamoto et al [32] used successive extraction wherein organic Hg was first extracted by shaking the sediment samples with chloroform and the extracted organic Hg was subsequently back-extracted with 0.01 mol L − 1 sodium thiosulfate. In order to separate Hg(II) oxide from Hg(II) sulfide, the residue was treated with 0.05 mol L − 1 H 2 SO 4 in order to extract only Hg(II) oxide.…”