Extended characterization of a vacuum gas oil by offline LC‐high‐temperature comprehensive two‐dimensional gas chromatography

Abstract

In a context of environmental preservation, purification and conversion of heavy petroleum cuts into high-quality fuel becomes essential. The interest for the characterization of those very complex matrices becomes a trendy analytical challenge, when it comes to get molecular information for the optimization of industrial processes. Among new analytical techniques, high-temperature 2-D GC has recently proved its applicability to heavy petroleum matrices, but lacks in selectivity to separate all chemical groups. To gain resolution, heart cutting is demonstrated for LC separation of saturated, aromatic and polar compounds prior to high-temperature 2-D GC. Therefore, an extended global resolution was obtained, especially by a better distinction of saturated compounds. This includes iso-paraffins and biomarker polynaphthenic structures, which are impossible to quantify with MS methods. This new way to analyze heavy petroleum fractions gives innovative opportunities for the construction of global weight distributions by carbon atoms number and by chemical families. This can right now be employed for quantitative analysis of heavy petroleum fractions and for studying conversion processes.

Size‐exclusion chromatography for the determination of the boiling point distribution of high‐boiling petroleum fractions

“…The possibility of collection of fractions with a specific range of boiling points of crude oil as well as distillates or other feedstocks is an undisputed advantage of the developed procedure. The developed procedure supplements of the existing LC x GC methodologies used for a detailed characteristic of petroleum products and determination of selected components .…”

The pre‐separation of oxygen containing compounds in oxidised heavy paraffinic fractions and their identification by GC‐MS with supersonic molecular beams.

“…The number of hydrocarbon isomers significantly increases with increasing carbon number, adding to the complexity of these heavy oxidised paraffinic fractions . The high number of compounds as well as the reduced chromatographic separation at high‐temperature conditions results in inevitable coelution of peaks …”

“…Multidimensional chromatographic systems have been used to address the complexity of heavy oxidised paraffinic samples and the peak coelution observed when analysed by GC. High‐temperature comprehensive two‐dimensional GC (HT‐GC × GC) was used to increase peak capacity and analyse complex heavy petroleum samples …”

“…6 The high number of compounds as well as the reduced chromatographic separation at high-temperature conditions results in inevitable coelution of peaks. 7 The second challenge is the accurate identification of the oxygenates present in these heavy oxidised paraffinic fractions by electron ionisation (EI) mass spectrometry (MS). The use of EI mass spectral libraries for identification is of limited applicability because the mass spectra of most of these heavy oxygenates are not available.…”

“…High-temperature comprehensive two-dimensional GC (HT-GC × GC) was used to increase peak capacity and analyse complex heavy petroleum samples. 6,7,[15][16][17][18][19][20][21] Another way of reducing the sample complexity prior to HT-GC analysis is to apply a fractionation step prior to the analysis by GC. [22][23][24][25][26] Solid-phase extraction (SPE) is one of the most widely used methods for extraction, sample clean-up, analyte concentration, and fractionation of organic compounds from a number of sample matrices.…”