Queipo-Abad S., Lagane Christelle, Point David. (2020). Sensitive determination of methylmercury delta C-13 compound specific stable isotopic analysis by purge and trap gas chromatography combustion isotope ratio mass spectrometry. Journal of Chromatography A, 1617, p. art. 460821 [8p.]. ISSN 0021-9673.
Titre du document
Sensitive determination of methylmercury delta C-13 compound specific stable isotopic analysis by purge and trap gas chromatography combustion isotope ratio mass spectrometry
Journal of Chromatography A, 2020,
1617, p. art. 460821 [8p.] ISSN 0021-9673
Despite several decades of mercury research, answering fundamental questions on where and how methylmercury (CH3Hg) toxin is naturally produced in aquatic ecosystems, is still highly challenging. Investigating complex and/or coupled processes in the context of global changes requires new high-resolution analytical tools. The purpose of the compound specific carbon stable isotopic analysis (delta C-13-CSIA) of the methyl group of methylmercury (CH3Hg), is to explore how the carbon cycle contributes to CH3Hg sources and formation pathways. The main problem associated with recent CH3Hg delta C-13-CSIA methods is the limited sensitivity when using Liquid Injection (LI)-GC-C-IRMS techniques, requiring several micrograms of CH3Hg (as Hg). In this work, we present the development and application of an original Purge-&-Trap system (PT) coupled to a GC-C-IRMS with the purpose of transferring and analyzing the total amount of CH3Hg available in a sample vial in the low nanogram range. The new PT-GC-C-IRMS system enhance the sensitivity by a factor better than 200, relative to LI-GC-C-IRMS, by minimizing the sample mass requirements. The delta C-13(CH3Hg) values obtained, following the same sample derivatization approach coupled to PT-GC-C-IRMS (-53.5 +/- 1.9 %), were in good agreement with the ones obtained in a previous study (-53.8 +/- 1.1 %). The standard solution was prepared from the same salt, requesting only 25-200 ng of CH3Hg (as Hg). This new methodology represents a milestone towards the analysis of large array of biological samples displaying CH3Hg concentrations in the low-mid ng g(-1) range, in order to explore the meaning of the carbon stable isotopic signature of CH3Hg in the environment.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
