Ion Chromatographic Determination of CrO42-, MoO4, WO42-, asO43- And SeO42- Ions in Aqueous Samples

M. C. Mehra, C. Pelletler and K. Ayikoe

Chemistry and Biochemistry Department, Universite de Moncton, Moncton NB E1A 3E9, Canada.

ABSTRACT:

An ion chromatographic approach is proposed for microanalysis of Cr, Mo, W, As and Se oxyanions in an aqueous system. The ions CrO42-, MoO4, WO42-, AsO43- And SeO42- are chromatographable on a low capacity polymer based analytical column. Quantification in an isocratic mode in //g range is feasible with 4-amino-2- hydroxybenzoic acid as mobile phase. At 4 mM in pH 6.5-6.8 range with 1 -1.5 mL/min flow rate all anions except CrO42- are analyzable by indirect spectrophotometry at 320 nm, while at 370 nm it is quantifiable in direct spectrophotometric mode. Speciation of Cr6+ and Cr3+ is feasible through prior oxidative conversion of Cr3+ to absorbing hexavalent CrO42- form by refluxing it in slightly alkaline medium with hydrogenperoxide. Analytical sensitivity for Cr3+ converted as chromate at 0.04 ppm compares favourably with the Atomic absorption spectrophotometry.

KEYWORDS:

Ion chromotography; UV- visible detection; chromate; molybdate; tungstate; arsenate and selenate ions; microanalysis.

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Copy the following to cite this article: Mehra M. C, Pelletler C, Ayikoe K. Ion Chromatographic Determination of CrO42-, MoO4, WO42-, asO43- And SeO42- Ions in Aqueous Samples. Orient J Chem 1993;9(3).

Copy the following to cite this URL: Mehra M. C, Pelletler C, Ayikoe K. Ion Chromatographic Determination of CrO42-, MoO4, WO42-, asO43- And SeO42- Ions in Aqueous Samples. Orient J Chem 1993;9(3). Available from: http://www.orientjchem.org/?p=38492