Study of the isotopic composition of mercury: experimental approach

The main objective of this work was to study experimentally the isotopic fractionation of mercury Hg, in derivatization processes i.e. Ethylation and Propylation. The multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) technique makes it possible to measure isotopic signatures of mercury stable elements efficiently in extremely compact i.e. 1ppb and 10ppb concentration systems. This device made it possible to study the evolution of mass independent fractionation (MIF) and mass dependent fractionation (MDF) under different conditions. According to our results, the MIF or the so-called anomalies are observed only for the odd isotopic mercury (199Hg and 201Hg). The study conducted from the samples, reveals the presence of a maximum anomaly for hydrochloric acid (HCl) 3% in concentration equal to +1.2 ‰ for Δ201Hg, but also the presence of a negative anomaly, equal to -0.43 ‰ for Δ201Hg at 10% concentration of HCl. As derivatization procedure, direct aqueous phase methylations and propylation were tested on the sample. The different methods of derivatization are compared.