Serum and tissue selenium contents related to renal disease and colon cancer as determined by electrothermal atomic absorption spectrometry

Microwave digestion with nitric acid and hydrogen peroxide was applied to the determination of selenium in biological tissues by Electrothermal Atomic Absorption Spectrometry (ETAAS). Validation of this method is presented in terms of adequate recovery of selenium from standard reference materials and the method is applied to carcinogen human colon tissue. Ultramicrofiltration was used to study selenium protein binding and its fractionation and speciation in blood serum. These studies showed that 95% of the total selenium in serum seems to be bonded to high-molecular-weight proteins. Experiments with renal failure patients showed lower selenium levels than in the health population (0.57+/-0.23 mM versus 0.81+/-0.11 mM). A wider distribution pattern of total serum selenium concentration (from 0.1 to 1 mM) was clearly observed in renal failure patients. However, the ultramicrofiltrable selenium fraction was always constant, even in the presence of desferrioxamine (DFO).