Determination of selenium in staple foods and total diets by electrothermal atomic absorption spectrometry without solvent extraction

Chemical modifiers were tested for overcoming interferences encountered in the determination of Se in biological materials by electrothermal atomic absorption spectrometry using Zeeman-effect background correction. The interferences were shown to be due to the presence of phosphate and Fe in the analysed samples. The experiments carried out proved that a mixture of PtIV(0.75%) and Mg(NO3)2(0.25%) was the most efficient for removing the observed interferences and resulted in the best stabilizing effect for Se. A method employing the above modifier was found to be suitable for the determination of Se in staple foods and total diets, tested employing food reference materials with recommended concentrations of Se.