DETERMINATION OF SELENIUM BY FLOW-INJECTION ANALYSIS BASED ON THE SELENIUM(IV)-CATALYZED REDUCTION OF 3-(4,5-DIMETHYL-2-THIAZOLYL)-2,5-DIPHENYL-2H TETRAZOLIUM BROMIDE

A novel flow injection method has been developed for the determination of selenium in biological samples. The method is based on a selective catalytic effect of Se(IV) on the reduction of 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide (MTT). The calibration line ranged over 1.3 pmol to 1.2 nmol of selenite with a detection limit of 0.63 pmol. Interference from the copper ion could be eliminated by an on-line adsorption of Cu on an ODS column as a Cu-bathocuproine disulfate chelate. The utility of the method was demonstrated by determining the selenium content in a standard sample.