Determination of zinc and cadmium in small amounts of biological tissues by microwave- assisted digestion and flow injection atomic absorption spectrometry

A microwave oven/flow injection/amotic absorption spectrometric system that permits the determination of zinc and cadmium in small samples of human kidney and liver tissue (ca. 1 g) is described. Digested samples are pumped to a closed flow circuit from which aliquots (20 λ for Zn and 100 μl for Cd) are injected for atomic absorption spectrometry. Precision (ca. 2–6% RSD) and recovery (97–103% for Zn and 96–98% for Cd) are good. Accuracy is confirmed by standard additions and use of standard reference materials. Data obtained for male and female human liver and kidney samples are presented.