ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Determination of Arsenic in Soils by Cathodic Stripping Voltammetry

D. Rúriková and A. Beňo

Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, CS-842 15 Bratislava

Abstract: An analytical procedure has been developed for determination of low contents of As in soils by the cathodic stripping voltammetry method using HMDE. Arsenic was determined after AsBr₃ extraction from the medium of 11.5 M-H₂SO₄, 0.05 M-NaBr, and 0.002 M-NH₂NH₂.H₂SO₄ into toluene and back-extraction into the solution of 1.5 M-HCl and 0.03 M-NH₂NH₂.H₂SO₄. Optimum procedure for decomposition of the soil sample and for separation of As from the interfering components as well as optimum conditions for electrochemical determination itself were investigated. Deposition of As on HMDE was achieved in the presence of Cu(II) by electroreduction in the form of intermetallic compounds from the medium of 1 M-HCl, 0.02 M-NH₂NH₂.H₂SO₄, and 0.0002 M-CuCl₂. Concentration of As was evaluated by the method of standard additions on the basis of the signal arising on reduction of As to AsH₃. The developed procedure is simple as to the number of operations preceding the determination itself and reliable, as evidenced by low values of relative standard deviations (1.1 to 3.2 %) and by the results of analyses of standard materials.

Full paper in Portable Document Format: 461a23.pdf

Chemical Papers 46 (1) 23–27 (1992)