Two-dimensional gas chromatography-online hydrogenation for improved characterization of petrochemical samples

Abstract

The Fischer-Tropsch (FT) process produces a variety of hydrocarbons over a wide carbon number range and during subsequent product workup a large variety of synthetic fuels and chemicals are produced. The complexity of the product slate obtained from this process is well documented and the high temperature FT (HT-FT) process products are spread over gas, oil and water phases. The characterization of these phases is very challenging even when using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-TOF-MS). Despite the increase in separation power, peak coelution still occurs when samples containing isomeric compounds are analysed by comprehensive two dimensional GC. The separation of cyclic and double bond containing compounds and combinations thereof is especially difficult since these compounds elute in a similar position on the GC×GC chromatogram and have identical molecular masses and similar fragmentation patterns. Pre-separation of alkenes and alkanes with HPLC prior to the GC×GC-TOF-MS analysis was used to distinguish between the cyclic and non-cyclic isomers of both these compounds. Subsequently, a method utilizing supercritical fluid chromatography (SFC) as an on-line pre-fractionation step was also developed. These pre-fractionation methods cannot be used to distinguish between classes like dienes and cyclic olefins since both contain alkene double bonds that will form adducts with the silver ions in these methods. On-line hydrogenation after GC×GC separation is a possible way to distinguish between these compounds since the number of rings and alkene double bonds can be determined from the mass spectra of the compounds before and after hydrogenation. This paper describes development of a GC×GC method with post column hydrogenation for the determination of the backbone of cyclic/olefinic structures enabling 2 us to differentiate between classes like dienes and cyclic olefins in complex petrochemical streams.

Comprehensive detection of analytes in large chromatographic datasets by coupling factor analysis with a decision tree

“…This technique has yielded valuable insights into atmospheric composition (Hamilton, 2010), but the increased complexity of the instrumentation and more stringent requirements for the mass spectrometer (e.g., time resolution faster than ∼ 50 Hz; Worton et al, 2012) have limited adoption of GC × GC. Furthermore, despite the higher resolving power, co-elution of peaks still occurs (Potgieter et al, 2016) when highly complex samples are analyzed, and challenges remain in the data analysis. Therefore, it is consequently common for analyses of environmental data to focus on the resolution and quantification of only a subset of specific analytes of interest and leave a large fraction of data unprocessed and unused.…”

Analytics Driving Kinetics: Advanced Mass Spectrometric Characterization of Petroleum Products

“…Parsons et al, 469 Aromatic species, alkenes, and alkynes in diesel fuel Ristic et al, 470 2016 Nitrogen-containing compounds in shale oil GC×GC-NCD Potgieter et al, 471 2016 Cyclic/olefinic structures in complex petrochemical streams Qiao et al, 472 2016 Chlorinated paraffins in sediments Zhang et al, 468 2016 Diamondoids in crude oil samples GP-MSE Chattopadhyay et al, 473 2017 Hydrocarbon class composition (paraffins, naphthenes, monoaromatics, diaromatics, and polyaromatic hydrocarbons) and trace level of benzene, toluene, ethylbenzene, and xylene in raffinate column bottom HPLC (ASTM D6591)…”

The Preparation of Novel Amino Acid Imidazole Ionic Liquids and Their Application as Stationary Phase for Capillary Gas Chromatographic Separations

“…Capillary gas chromatography (GC) is a powerful method in the separation and analysis of organic mixtures [1] . It has been extensively used in petrochemical, materials, biological medicine, environmental pollution detection, food safety evaluation and pharmaceutical anlaysis fields because of its inherent advantages of simplicity, high resolution, high selectivity, high sensitivity, short analysis time and low cost [2–16] . In GC, chromatographic stationary phase plays a key role in the high‐resolution separation of analytes [17–19] .…”

“…[1] It has been extensively used in petrochemical, materials, biological medicine, environmental pollution detection, food safety evaluation and pharmaceutical anlaysis fields because of its inherent advantages of simplicity, high resolution, high selectivity, high sensitivity, short analysis time and low cost. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] In GC, chromatographic stationary phase plays a key role in the highresolution separation of analytes. [17][18][19] Therefore, the development of high performance chromatographic stationary phase has important theoretical and practical significance.…”