Determination of total tin in evironmental and geological samples by electrothermal atomic absorption spectrometry using a tungsten furnace after pretreatment by solvent extraction and cobalt(III) oxide collection

Abstract

Solvent extraction and cobalt(III) oxide collection has been studied for the determination of total tin in environmental and geological samples by electrothermal atomic absorption spectrometry using a tungsten furnace. Tin iodide was extracted into benzene under acidic conditions using sulfuric acid, and cobalt(III) oxide powder was added to the benzene to collect the extracted tin. The cobalt(III) oxide powder was separated from benzene by vacuum filtration and then suspended in 5 ml water. Part of the slurry thus obtained was introduced into the tungsten furnace and the determination of tin performed. A relative standard deviation of 1.8% (n=6) was obtained for the determination by the proposed method of 0.20 mg l ^–1 tin in the slurry. The calibration curve was linear up to 0.40 mg l ^–1 (4.0 ng per 10 µl) tin, and the detection limit (3 σ) was 6.00 µg l ^–1 (0.06 ng per 10 µl) tin. The proposed method was applied to marine sediment, fish tissue and rock as examples of environmental and geological samples. The determination of total tin obtained was in good agreement with the certified value or reference value of the environmental and geological samples.