Direct determination of selenium in solid biological materials by graphite furnace atomic absorption spectrometry

Abstract

A graphite furnace atomic absorption spectrometric method is described for the direct determination of selenium in microgram amounts of solid biological materials, using the so-called cup-in-tube technique. Spectral interferences were minimised by using Zeeman-effect background correction and a “normal” heating rate during atomisation. The stabilising efficiencies of nickel and palladium on selenium were investigated by means of radioactive measurements, and only palladium was found to be useful. The accuracy of the method was established by analysing a number of reference materials. Good agreement with certified/recommended values, and an over-all precision of 10% at the 1 µg g^–1 level was obtained using standardisation against a graph based on additions to a solid sample. The method was applied to insulin-producing cell pellets, which could be analysed using standardisation against an aqueous standard graph. The detection limit for selenium in a solid material is 0.15 µg g^–1 for a typical sample mass of 0.5 mg.