Determination of selenium in blood and plant material by hydride generation and atomic-absorption spectroscopy

Abstract

A method is described for the routine determination of selenium in blood and plant samples at concentrations in the range 0.01–0.50 µg g^–1. Samples of mass 1 g are digested with nitric and perchloric acids and then selenium hydride is generated from diluted digests by the controlled introduction of a solution of sodium borohydride. The selenium is subsequently atomised in a nitrogen-hydrogen-entrained air flame. Digests can be analysed at a rate of four per minute. For a pasture sample, which contained a 0.038 µg g^–1 concentration of selenium, and a blood sample, which contained 0.029 µg g^–1 of selenium, relative standard deviations of 7.9 and 4.3%, respectively, were obtained. The mean recovery of added selenium was 100.5%, with a relative standard deviation of 4.7%. The efficiency of hydride generation was 95%.