Evaluation of Quantitative Sulfur Speciation in Gas Oils by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Validation by Comprehensive Two-Dimensional Gas Chromatography

Abstract

Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has been applied for the quantitative speciation of sulfur containing compounds in gas oil (GO). For this purpose, ionization and mass spectrometric parameters have been studied and optimized with a set of standard compounds and GO samples. Comprehensive two-dimensional gas chromatography (GCxGC) was used as the reference method. To allow a quantitative comparison between FT-ICR MS and GCxGC results for GO samples, FT-ICR MS parameters were optimized and data obtained by both techniques were standardized. Response factors were established for two ionization modes: atmospheric pressure photo ionization (APPI) and electrospray after selective derivatization of sulfur compounds (MeESI). To test the validity of the developed MS methods, a third GO was analyzed and response factors were applied. Comparison with GCxGC results showed good agreement for sulfur families (deviation within 5% and 15% for MeESI and APPI data, respectively). Abundances of individual isomer groups match within 40% in most cases. These results principally demonstrate the suitability of FT-ICR MS for a quantitative analysis of sulfur compounds (by DBE and carbon number distribution pattern) in petroleum middle distillates. This approach has the potential to be extended to higher-and non-boiling petroleum fractions where quantitative speciation is presently not available.

Atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry for complex thiophenic mixture analysis

“…These observations show that the relative abundances of the model components do not closely reflect the relative concentrations of the neutrals in the sample because of the ionization preference for standards with high DBE values or carbon numbers or concentration. The demonstrated particular effect of aromatic size of PASH over response behavior in APCI agrees well with a similar study of PASHs investigated using APPI …”

“…The persistence of some PASHs means they will survive the HDS and may lead to environmental problems because their combustion liberates SO 2 which contributes to acid rain . Thus, speciation of sulfur compounds and monitoring their distribution in various crude oil fractions have rapidly grown in the last years . Detailed knowledge of the composition of complex PASH patterns is important for an efficient production and refining process of crude oil resources.…”

Application of pyrolysis–mass spectrometry and pyrolysis–gas chromatography–mass spectrometry with electron-ionization or resonance-enhanced-multi-photon ionization for characterization of crude oils

“…However, the EI to REMPI (266 nm) ratio is substance-specific and depends on the used wavelength. [10,37] A C C E P T E D M A N U S C R I P T…”

“…PASH and PAH are similar in properties and they often have the same nominal mass [9]. The most dominant representatives of PASH in crude oils are thiophene, benzothiophene (BT), dibenzothiophene (DBT) and benzonaphtothiophene (BNT) [10]. In the last years there has been much research dedicated to the separation and detection of PAH and PASH using GC based techniques [4,[9][10][11]12,13], but especially for the high molecular fraction new analytical techniques or methods are still needed.…”

Effect of CO2 on catalytic hydrotreatment of gas‐oil

“…The most important heteroatom that must be removed in order for the product to satisfy the strict fuel specifications is sulfur. Gas‐oil includes a large number of sulfur‐bearing compounds that can be classified as thiols, sulphides, disulphides, thiophenes, dibenzothiophenes, and benzonaphthothiophenes, covering a wide spectrum of desulfurization reactivity . According to recent legislative regulations, diesel sulfur content must not exceed 10 ppm, imposing demanding refining processing to abide by such restrictions.…”