Characterization of Nitrogen-Containing Compounds in Heavy Gas Oil Petroleum Fractions Using Comprehensive Two-Dimensional Gas Chromatography Coupled to Time-of-Flight Mass Spectrometry

Abstract

Nitrogen (N)-containing compounds are naturally present in petroleum, and they are responsible for several deleterious effects that reduce the quality of products and negatively affect the processes involved in the upgrading of feedstock. The speciation of such compounds in petroleum heavy fractions is still a challenge. In the present work, N-containing compounds were characterized in heavy gas oil (HGO) fractions using a solid−liquid fractionation scheme and comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. Classification and identification of compounds were carried out based on seven different categories of analytical information viz. retention times in first and second dimensions, analytical standards co-injection, the structured pattern of the separation space, the structured pattern of the separation space with the selection of specific m/z values, the library mass spectra match factor, and the characteristic deconvoluted mass spectra. All of these interpretations were available from a single analytical run followed by a standard injection. Compounds were extracted from the sample using an ion-exchange resin method to separate neutral and basic N-containing compounds, after a pre-fractionation step, using neutral aluminum oxide. This methodology allowed for the identification of 120 N-containing compounds and tentative identification of a further 108 compounds using their deconvoluted characteristic mass spectra as a basis for identification. Identified components included alkyl-indols, alkyl-carbazols, alkyl-benzocarbazols, alkyl-quinolines, alkyl-indene-pyridines, alkyl-benzoquinolines, and alkyl-dibenzoquinolines.

Chromatographic Methods Applied to the Characterization of Bio-Oil from the Pyrolysis of Agro-Industrial Biomasses

“…GC × GC allows the utilization of several detectors, with few modifications to adapt them to the low volume and high velocity of data processing. One can be highlight the flame ionization detector (FID), time-of-flight mass spectrometry (TOF-MS) and quadrupole mass spectrometry (qMS) as the more used [197][198][199][200][201][202][203].…”

Use of comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for the characterization of biodegradation and unresolved complex mixtures in petroleum

“…doi:10. 1016/j.gca.2010.08.024 are grouped into distinct patterns in the two-dimensional (2D) chromatographic plane providing useful information on both their boiling point and polarity; relationships of structured retentions have proved especially useful for molecular identification of nitrogen-containing compounds in 'heavy gas oil' petroleum products, using GC Â GC/ time-of-flight mass spectrometry (TOFMS) (von Mü hlen et al, 2010). These analytical benefits make GC Â GC particularly suited for the chemical analysis of crude oils and related samples, as well as for tracking compositional changes of petroleum products affected by biodegradation or weathering, such as in oil spills.…”

Class Type Separation of the Polar and Apolar Components of Petroleum

“…For instance, nitrogen containing compounds in crude oils are present as both neutral (indoles, carbazoles, and pyrroles), and basic nitrogen (pyridinic and quinolines) species. Interests in these compounds are primarily focused on their tendency to poison processing catalysts [1][2][3] , reduce product stability [4] , and on their associated toxicity in environmental scenarios (i.e. [5] ).…”

“…The mass spectrometer settings were: nitrogen sheath, auxiliary, and sweep gas (53,14, and 3 Arbitrary units, respectively), vaporiser temperature (300 °C), polarity (positive or negative ion), spray voltage (+3500/ -2500 V), capillary temperature (270°C) and S-lens RF level (50). The resolution was set at 70,000 at m/z 200 with a full scan (m/z 100 -1000), AGC target (1e 6 , automatic gain control) and micro scans (1). External mass calibration (≤3 ppm) was used with auto-calibration using Pierce LTQ Velos ESI positive ion calibration solution (n-butylamine, caffeine, MRFA, and Ultramark 1621 (Thermo Fisher Scientific, UK)) and Pierce LTQ Velos ESI negative ion calibration solution (sodium dodecylsulfate, sodium taurocholate and Ultramark 1621 (Thermo Fisher Scientific, U.K.).…”