DETERMINATION OF TRACE-METALS (CD, PB) IN FISH BY ELECTROTHERMAL ATOMIC-ABSORPTION SPECTROMETRY AFTER MICROWAVE DIGESTION

A method is elaborated to determine cadmium and lead in biological tissues. 0.2 g samples of muscle of chub were digested with 1.8 mi concentrated nitric acid in a commercially available microwave digestion bomb and analysed with a Zeeman-effect background corrected atomic absorption spectrometer. The concentrations of cadmium and lead in the muscles of fish ranged between 6-8 ng g(-1) and 30-40 ng g(-1), respectively, whereby the detection limit was 0.14 ng ml(-1) for cadmium and 6.4 ng ml(-1) for lead. The analytical results for the determination of Cd and Pb indicated that the applied microwave digestion gave low acid blank concentrations. Additionally, microwave heating is rapid and safe and a reduction of acid volume can be realized.