Determination of selenium by graphite furnace atomic absorption spectrometry. Part 2. Role of nickel for analyte stability

Abstract

The chemistry involved in the determination of the selenium in the presence of nickel nitrate and nickel chloride was investigated for various furnace conditions and matrix compositions. To obtain a deeper understanding of this complex system, we had to combine information from several techniques such as mass spectrometry, radioactive measurements, thermodynamic calculations and AAS measurements using different types of graphite material and furnace designs. It is shown, and discussed, why nickel alone is not sufficient to stabilise selenium if an excess of organic material is present. Furthermore, experimental results obtained by using a two-step constant temperature furnace indicate that the presence of glucose decreases the number of free atoms formed during atomisation.