The voltammetric determination of cobalt(II) in seawater – adsorptive preconcentration of the dimethylglyoxime complex

Autor:	G. W. VanLoon, W. W. Westenbrink, J. A. Page
Rok vydání:	1990
Předmět:	Drop (liquid) Organic Chemistry Inorganic chemistry Analytical chemistry chemistry.chemical_element General Chemistry Catalysis Mercury (element) chemistry.chemical_compound Anodic stripping voltammetry Dimethylglyoxime Adsorption chemistry Seawater Trace analysis Cobalt
Zdroj:	Canadian Journal of Chemistry. 68:209-213
ISSN:	1480-3291 0008-4042
DOI:	10.1139/v90-027
Popis:	Conditions for the determination of trace Co in seawater are described. The method involves formation of the dimethylglyoxime complex and adsorptive accumulation onto a hanging mercury drop electrode at an applied potential of −0.70 or −0.96 V vs. SCE. The adsorbed complex is then reduced by scanning the electrode potential to −1.20 V; the reduction peak potential (Ep) is −1.12 V. Nickel behaves in a similar manner with Ep of −0.99 V but the Co complex appears to be preferentially adsorbed, making analysis for Co possible even in the presence of a large excess of Ni. Adsorption of organic matter also occurs; this does not affect analytical sensitivity but limits the maximum deposition time allowed in the analysis.Determination of Co in six seawater samples yielded results ranging from 4 to 114 ng L−1. Good agreement was obtained with the one reference sample (NASS-1) for which there was a certificate value. Keywords: cobalt, dimethylglyoxime, stripping voltammetry, adsorption, seawater.
Databáze:	OpenAIRE
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