SELENIUM DETERMINATION IN BOVINE LIVER BY HYDRIDE GENERATION - ATOMIC-ABSORPTION SPECTROPHOTOMETRY

The determination of selenium (Se) in bovine liver requires a sensitiv e method due to the low content of this element in such tissue. The hy dride generation-atomic absorption technique responds to this requirem ent, and is also recognized for its simplicity and accuracy. The sampl e dissolution is required. The organic matrix must be completely destr oyed, but without analyte losses. In this work, a simple procedure for the Se determination in bovine liver is presented: a 10:1 nitric-perc loric (mixture) is added to 10 mg of the powdered and dried sample, in quartz open tubes. The mixture is allowed to stand overnight and then heated, stepwise, to 140 degrees C (60') and 210 degrees C. Selenium was determined in the resulting solution by hydride-generation-AAS. Th e detection limit of the who le analytical procedure was 0,5 ng (n=10, k=3). A very good concordance between found and certified values was observed in the analysis of a standard reference material - NIST 1577a , bovine liver. The procedure permitted the determination of Se concen tration above 0,1 mu g/g in the dried material.