The detailed characterisation of middle distillates is essential for a better understanding of reactions involved in refining process. Owing to higher resolution power and enhanced sensitivity, comprehensive two-dimensional gas chromatography (GC x GC) is a powerful tool for improving characterisation of petroleum samples. The aim of this paper is to compare GC x GC and various ASTM methods -- gas chromatography (GC), liquid chromatography (LC) and mass spectrometry (MS) -- for group type separation and detailed hydrocarbon analysis. Best features of GC x GC are demonstrated and compared to these techniques in terms of cost, time consumption and accuracy. In particular, a new approach of simulated distillation (SimDis-GC x GC) is proposed: compared to the standard method ASTM D2887 it gives unequal information for better understanding of conversion process.

Résumé -Chromatographie en phase gazeuse bidimensionnelle pour l'analyse détaillée des produits pétroliers -La chromatographie gazeuse bidimensionnelle intégrale (CG×CG) représente une avancée majeure pour l'analyse détaillée des produits pétroliers. Cette technique est fondée sur deux dimensions orthogonales que forme l'association de deux colonnes de CG de sélectivités de séparation différentes. L'échantillonnage à haute fréquence à l'interface des deux colonnes permet que la totalité du produit soit transférée et analysée dans les deux dimensions. Ainsi, la capacité de pics et le pouvoir résolutif sont nettement accrus. En outre, les chromatogrammes 2D sont structurés en fonction des propriétés de volatilité et de polarité des hydrocarbures ce qui facilite leur identification. Dans cet article sont présentés les concepts et le principe de mise en oeuvre de la CG×CG. Un système prototype a été développé à l'IFP comprenant notamment un modulateur à double-jets de CO 2 et un logiciel de posttraitement pour la visualisation et l'intégration des chromatogrammes. Les exemples d'application choisis illustrent le potentiel de la technique pour la caractérisation détaillée de distillats moyens, la spéciation de composés soufrés dans les gazoles et l'analyse approfondie des effluents de procédés pétrochimiques. Abstract -Comprehensive Two-Dimensional Gas Chromatography for Detailed Characterisation of Petroleum Products -Comprehensive two-dimensional gas chromatography (GC×GC) is a major advance for the detailed characterisation of petroleum products. This technique is based on two orthogonal dimensions of separation achieved by two chromatographic capillary columns of different chemistries and selectivities. High-frequency sampling between the two columns is achieved by

The monitoring of total sulfur content and speciation of individual sulfur-containing compounds in middle distillates is required for efficient catalyst selection and for a better understanding of the kinetics of the reactions involved in hydrotreament processes. Owing to higher resolution power and enhanced sensitivity, comprehensive two-dimensional gas chromatography (GCxGC) hyphenated to sulfur chemiluminescence detection (SCD) has recently evolved as a powerful tool for improving characterization and identification of sulfur compounds. The aim of this paper is to compare quantitatively GCxGC-SCD and various other methods commonly employed in the petroleum industry, such as X-ray fluorescence, conventional GC-SCD, and high-resolution mass spectrometry, for total sulfur content determination and speciation analysis. Different samples of middle distillates have been analyzed to demonstrate the high potential and important advantages of GCxGC-SCD for innovative and quantitative analysis of sulfur-containing compounds. More accurate and detailed results for benzothiophenes and dibenzothiophenes are presented, showing that GCxGC-SCD should become, in the future, an essential tool for sulfur speciation analysis.

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