Author/Editor		Kajič, Petra; Milošev, Ingrid; Pihlar, Boris; Pišot, Venčeslav
Title		Determination of trace cobalt concentrations in human serum by adsorptive stripping voltammetry
Type		članek
Source		J Trace Elem Med Biol
Vol. and No.		Letnik 17, št. 3
Publication year		2003
Volume		str. 153-8
Language		eng
Abstract		The goal of our study was to develop an accurate and reliable method for determining trace cobalt concentrations in human serum. The method was used to determine cobalt in the sera of healthy persons and patients with orthopaedic implants containing cobalt - a possible source of systemic release of cobalt into the human body. This goal is of vital interest since cobalt and its compounds are classified by IARC as potentially carcinogenic to humans. We used an electrochemical method, adsorptive stripping voltammetry (AdSV), which made possibte the low detection limit and high sensitivity needed for measurements in human serum. The serum was acid digested by a combination of H2S04, HN03 and H202 in a 10 mL Kjeldhal flask. The digested sample was then dissolved in 0.1 mol/L ammonia buffer, pH 9.0 ± 0.2. The determination is based on the adsorptive collection of the complex of cobalt (II) with dimethylglyoxime on a hanging mercury drop electrode (HMDE). The optimum values of adsorption potential and time were determined to be -0.8 V and 60 s. The optimisation of the sample digestion protocol and measurement procedures ensured the reliable assessment of low cobalt concentrations, down to 0.03 micro g/L. The mean concentration of serum cobalt in four healthy persons was 0.11 ± 0.06 micro g/L, and in four patients with total hip replacements 0.34 ± 0.07 micro g/L. This method will be used routinely for measuring serum cobalt levels in patients with total hip replacements.
Descriptors		COBALT IMPLANTS, ARTIFICIAL ELECTROCHEMISTRY