Quantification of Hydrocarbons in Gas Oils by GC×GC-VUV: Comparison with Other Techniques

Abstract

Insight into the composition of middle distillates is essential to meet the requirements for product quality but also in terms of complying with ever more stringent environmental regulations. A newly introduced vacuum ultraviolet absorbance detector (VUV) possesses both quantitative and qualitative abilities and is amenable to hyphenation with comprehensive two-dimensional gas chromatography (GC×GC). It has good selectivity for hydrocarbon species and permits their differentiation even if they are not chromatographically separated. In this study, quantification of hydrocarbons in 14 gas oils coming from different origins was performed to evaluate the benefits of GC×GC-VUV for the analysis of middle distillates. Coelutions between hydrocarbon families were investigated and spectral decomposition was carried out for quantification of coeluted hydrocarbon families. Quantification obtained with GC×GC-VUV was compared with conventional techniques such as GC×GC-FID with prefractionation, MS method based on ASTM D2425, UV spectroscopic analysis, and bromine number. In general, good comparability was obtained between GC×GC-VUV and all the different techniques for major hydrocarbon families, however with a gain in time and/or information when using GC×GC-VUV. This demonstrates that GC×GC-VUV can be considered as a relevant tool for the detailed analysis of middle distillates, regardless of their origin.

Gas chromatography—vacuum ultraviolet spectroscopy in petroleum and fuel analysis

“…Lelevic et al examined middle distillates using a VUV detector hyphenated to multidimensional gas chromatography. 50 Some current methods that rely on mass spectrometry, for example, ASTM D2425, have been restricted to samples with a limited boiling point range and olefin content. These methods have difficulty differentiating between isomers, and the quantitation is time intensive.…”

Facilitating method development for reverse fill/flush flow modulation by using a tuneable auxiliary pressure source instead of a fixed bleed capillary

“…The schematic representation of both systems is provided in Figure S1 in the Supporting information. The FFF modulation system was employed in many works with good performance [10][11][12][13][14][15][16][17][18]. The RFF modulation system differs from the FFF by the fact the modulator channel is flushed in the inverse direction to the direction of the channel filling.…”

Quantitative performance of forward fill/flush differential flow modulation for comprehensive two-dimensional gas chromatography

“…The schematic representation of both systems is provided in Figure S1 in the Supporting information. The FFF modulation system was employed in many works with good performance [10][11][12][13][14][15][16][17][18]. The RFF modulation system differs from the FFF by the fact the modulator channel is flushed in the inverse direction to the direction of the channel filling.…”