Determination of total chromium, cobalt and silver in foodstuffs by flame atomic-absorption spectrophotometry

A method is described for the determination of total chromium, cobalt and silver in foodstuffs. Organic matter is destroyed by a wet-digestion procedure and the cobalt and silver are concentrated by chelation with diethylammonium diethyldithiocarbamate and extraction into 4-methylpentan-2-one. Chromium is then chelated with pentane-2,4-dione and separately extracted into 4-methylpentan-2-one. The concentrations of the three elements in the extracts are measured by flame atomic-absorption spectrophotometry.