Selenium preconcentration in a gold “amalgamator” after hydride generation for atomic spectrometry

SELENIO

ORO

ESPECTROMETRIA ATOMICA

BIBLIOGRAFIA NACIONAL QUIMICA

2020

A gold amalgamator, used conventionally for Hg vapor enrichment, is reported to preconcentrate Se after hydride generation. Optimum trapping and volatilization temperatures were 450 and 970 °C, respectively. Preconcentration processes are controlled by temperature only while carrier gas composition remains unchanged (75 ml min-1 H2). This is a significant advantage compared to the approach reported previously based on a gold wire, when Se preconcentration was controlled by both surface temperature and carrier gas composition. Moreover, the gold amalgamator offers higher capacity and better resistance towards interferences, at least by an order of magnitude. This approach to Se preconcentration is very well compatible with atomic absorption spectrometry using a modular trap-and-atomizer device reported recently. A limit of detection for 300 s sample introduction time reached 13 pg ml-1 Se (247 pg Se absolute). The method developed was validated by analysis of water certified reference materials. Mechanism of selenium hydride trapping was investigated employing 75Se radioactive indicator. Potential of coupling the gold amalgamator trap to an inductively coupled plasma mass spectrometer was also investigated. However, severe transport losses of volatilized Se species occur between the heated amalgamator and the torch due to analyte condensation on colder surfaces preventing this set-up from routine use.

Journal of Analytical Atomic Spectrometry v. 35, no. 10, 2020. -- p. 2132-2141

Royal Society of Chemistry

2020

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DOI:10.1039/d0ja00227e

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