Determination of Total Arsenic in Environmental and Geological Samples by Electrothermal Atomic Absorption Spectrometry Using a Tungsten Furnace after Solvent Extraction and Cobalt(III) Oxide Collection

Abstract

Abstract A separation method, using solvent extraction and cobalt(III) oxide collection, has been studied for determining the total arsenic in environmental and geological samples by electrothermal atomic absorption spectrometry (ETAAS) using a tungsten furnace. After arsenic iodide was extracted into benzene, cobalt(III) oxide powder was added to the benzene solution to collect the extracted arsenic. The cobalt(III) oxide was separated from benzene by vacuum filtration and then suspended in 5 cm3 of water. The slurry was introduced into the tungsten furnace and the determination of arsenic was performed. The relative standard deviation of the proposed method at the 0.20 mg dm−3 arsenic level was 2.4% (n = 10). The calibration curve obtained with the proposed method was linear up to 0.50 mg dm−3 (5.00 ng/10 mm3), and the detection limit (3σ) was 12 μg dm−3 (0.12 ng/10 mm3). The present method was applied to the analysis of some environmental and geological standard reference materials, and the concentrations of total arsenic obtained by the present method were in good agreement with the certified values or the reference values of those samples.