COMPARISON OF INSTRUMENTAL METHODS FOR THE DETERMINATION OF TOTAL SELENIUM IN ENVIRONMENTAL-SAMPLES

Choosing the appropriate instrumental method for the determination of total Se in environmental samples is difficult, considering the wide c hoice of methods currently available. By use of a sediment matrix, an objective comparison is made between fluorimetry, hydride generation a tomic absorption spectrometry (HGAAS), hydride generation inductively coupled plasma atomic emission spectrometry (HG-ICP-AES), hydride gene ration inductively coupled plasma mass spectrometry (HG-ICP-MS) and ra diochemical neutron activation analysis (RNAA) methods, involving tech nical criteria such as detection limits, reproducibility, time taken f or analysis and interferences. A novel flow injection (FI) system was constructed and adapted for AAS to improve the efficiency of HG system s and shows that the method of hydride sample injection can have a sub stantial influence on over-all performance. Consideration is given to the definition and use of the term limit of detection. The conclusions of the study are that fluorimetry, HGAAS and HG-ICP-AES will continue to be usefully employed for routine, laboratory analyses, although wi th the fluorimetric method, performance characteristics are inferior i n comparison with those of more recent analytical techniques. The FI-H GAAS method is superior to the single sample HGAAS system. For samples of low Se concentration, HG-ICP-MS and RNAA methods are superior.