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International audience; The speciation analysis of complex mixtures of chemicals requires an efficient separation method and supercritical fluid chromatography (SFC) is one such technique that has been used for these purposes. Hyphenation of SFC to inductively coupled plasma mass spectrometry (ICP-MS) can provide elemental speciation information. However, the hyphenation of modern SFC instrumentation to ICP-MS has not yet been tested. The aim of this study was to develop a novel interface to hyphenate ICP-MS and modern HPLC-like SFC systems that enable the use of organic solvent gradients and packed columns. For this, an optimization of the most important parameters, such as SFC back pressure, gas temperature and position of the interface within the whole set up, was carried out, and quantitative analyses in flow injection analysis (FIA) mode of two biolubricants and one pyrolysis oil were accomplished, reaching DLs at the ppb level with the tested mobile phase compositions. In addition, in order to test the performance of this novel interface with real samples, chromatographic separation experiments of one pyrolysis oil and one coal tar using a 2-picolylamine column were carried out, confirming the stability of this new interface and its potential to become a powerful speciation technique in the future.

International audience; This study describes the use of gel permeation chromatography inductively coupled plasma high-resolution mass spectrometry (GPC ICP HRMS) to examine and explain two important petroleum industry catalytic processes: hydrodemetallization (HDM) and hydrodesulfurization (HDS). The sulfur, nickel and vanadium species size distributions in atmospheric residue fractions were studied to track their evolution during both catalytic processes and examine their mechanisms, especially those mechanisms linked to changes in temperature and initial deactivation via coke laydown. Chromatogram shapes as well as peak areas were used to study the V, Ni and S aggregate types and concentrations in the feedstock as well as in the product after varying the operating temperature and residence time at a constant temperature. For the V and Ni compounds, the low and medium molecular weight (LMW and MMW, respectively) aggregates are easily hydrotreated under all conditions, while the high molecular weight (HMW) compounds are more refractory. For the S compounds, a different reactivity pattern was observed whereby the LMW, MMW and HMW aggregates were more similar in their reactivity, showing that the catalyst is less selective towards a certain aggregate size for the S compounds compared to the V or Ni compounds.

International audience; A method using liquid–liquid extractions has been developed for matrix simplification and evaluated by gel permeation chromatography coupled with inductively coupled plasma and mass spectrometry. In this method, maltenes were dissolved in n-heptane and extractions with methanol (MeOH), acetonitrile (ACN), and dimethylformamide (DMF) were performed. The extraction with ACN is more efficient than that with MeOH for the removal of compounds with low-molecular weights (LMW) containing V (our reference element) and more selective than that with DMF (with this solvent, compounds with LMW and medium-molecular weights (MMW) are extracted). Thus, a sequential extraction was performed by applying ACN to selectively remove LMW compounds, followed by extractions with DMF of the resulting maltene to separate the MMW compounds from the high-molecular weights (HMW) compounds remaining in the final remnant maltene. The results show, for the first time in the literature, that it is possible to separate the three V and Ni species of compounds present in maltenes based on their molecular weights (HMW, MMW, and LMW).