Influence of methane addition on selenium isotope sensitivity and their spectral interferences

Geerke H. Floor (1, 2) , Romain Millot (2) , Monica Iglesias (1) , Philippe Négrel (2)

1 Departament of Chemistry
2 BRGM - Bureau de Recherches Géologiques et Minières (BRGM)

The measurements of stable Se isotopic signatures by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) are very challenging, due to the presence of spectral interferences and the low abundance of Se in environmental samples. We systematically investigated the effect of methane addition on the signal of selenium and its interferences. It is the first time that the effect of methane addition has been assessed for all Se isotopes and its potential interferences using hydride generator multi collector inductively coupled plasma mass spectrometry (HG-MC-ICP-MS). Our results show that a small methane addition increases the sensitivity. However, the response differs between a hydride generator and a standard introduction system, which might be related to differences in the ionization processes. Both argon and hydrogen based interferences, the most common spectral interferences on selenium isotopes in HG-MC-ICP-MS, decrease with increasing methane addition. Therefore analyte-interference ratios and precision are improved. Methane addition has thus a high potential for the application to stable Se isotopes ratios by HG-MC-ICP-MS.

Keywords: selenium; isotopes; methane; multi collector ICPMS; interferences; precision; hydride generation

Domains: Sciences of the Universe [physics]; Earth Sciences; Geochemistry; Environmental Sciences; Global Changes

Geerke H. Floor, Romain Millot, Monica Iglesias, Philippe Négrel. Influence of methane addition on selenium isotope sensitivity and their spectral interferences. Journal of Mass Spectrometry, 2011, 46, pp.182-188. ⟨10.1002/jms.1880⟩. ⟨hal-00674027⟩