Determination of cobalt in blood

Abstract

Blood and serum have been wet oxidised with a nitric acid-perchloric acid-sulphuric acid mixture, and the cobalt has been extracted from the aqueous ash with 1-nitroso-2-naphthol in chloroform. Cobalt-57 tracer studies showed an over-all recovery of 95% of the cobalt. Carbon rod atomic-absorption spectrophotometry showed the following likely ranges for cobalt in healthy adult human beings: blood, 0.20–0.28 µg per 100 cm³; and serum, 0.12–0.20 µg per 100 cm³. The coefficient of variation of the entire analytical procedure is ±3–4%. The wide discrepancies between literature values for blood cobalt and details of the present method are discussed.