Graphite furnace atomic absorption spectrometric determination of selenium in plant materials following combustion in a stream of oxygen

Abstract

The determination of selenium in plant materials by graphite furnace atomic absorption spectrometry can be difficult not only because of the low levels of the element found in non-accumulating species, but because the technique is particularly prone to interferences from the sample matrix. The amelioration of these problems by the use of a commercially available combustion system in which the sample is burned in a stream of oxygen and the volatilised Se collected in a small volume of 2 M acetic acid containing hydrogen peroxide has been investigated. The performance of this system in combination with determination by atomic absorption spectrometry, using electrothermal atomisation with totally pyrolytic graphite furnace tubes and platforms, and copper as a matrix modifier, has been assessed. The results obtained from the analysis of three standard reference materials and nine herbage samples are presented. The limit of determination of the method is 3 ng g^–1 Se on a dry mass basis.