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

Determination of Inorganic Selenium Species in Natural Waters by Preconcentration and Cathodic Stripping Voltammetry

D. Rúriková and E. Tóthová

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

Abstract: This paper describes a method, which employs an anion-exchange procedure and differential pulse cathodic stripping voltammetry (DPCSV) with hanging mercury drop electrode in the presence of added copper(II) for the determination of low levels of inorganic selenium species in natural waters. Optimum procedure for preconcentration and separation of Se(IV) and Se(VI) as well as optimum conditions for electrochemical determination itself were investigated. The perconcentration/separation step prior to determination improves the detection limit and removes matrix interference. The detection limit of 10 ng dm-3 was obtained on the basis of enrichment factor of 15 and a 120 s deposition. The precision and accuracy of the pretreatment procedure and DPCSV technique were evaluated by analyzing synthetic water spiked with known amounts of Se(IV) and Se(VI). The relative standard deviations ranged from 0.3 to 3.5 % and the recoveries were > 95 % for both Se species. Finally, the developed method was successfully applied to the analysis of Se(IV) and Se(VI) in natural waters.

Full paper in Portable Document Format: 531a26.pdf

Chemical Papers 53 (1) 26–33 (1999)