Abstract: The determining method of trace selenium in animal viscera was studied by combining of oxygen bomb ash test and spectrophotometry. The samples of animal viscera were decomposed by burning with abundant oxygen in oxygen bomb. Then the selenium compound in different forms of food was either oxidized or decomposed to oxides or free selenium vapor, the decomposed product were fully absorbed by thick base liquid NaOH and then the pH value of absorbed liquid set to 5～8. In HCl a ternary complex solution was formed among Se(IV) I3- and crystal violet in the presence of PAV. The absorption maximum is 580nm. The concentration range of 0～0.25μg/ml of selenium obeys beer’s law. By separation on EDTA as shelter solvent and thiourea as reductive, the interference of most of the coexisting elements was eliminated. Equation of linear regression equation is C=0.4676A-0.0055, the related coefficient r is 0.9995 and the recovery rates were the range of 99.14%～100.79%. This method has been applied to the determination of trace selenium in animal internal organs with satisfactory results.

Key words: selenium, oxygen bomb combustion, animal internal organs