Analysis of Nitrogen Species in Gas Oils Using High Performance Liquid Chromatography and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

• Author / Creator

  Oro, Nicole E.

• The nitrogen content of products derived from oil sands bitumen is important, as nitrogen causes problems in upgrading and hydrotreating. Normal phase high performance liquid chromatography (HPLC) has been previously used to attempt separation of the nitrogen group types (pyrrole and pyridine) found in petroleum, but complete separation in a single step has not been achieved. High resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) has been used successfully for the detailed analysis of nitrogen content in petroleum samples (petroleomics), but HPLC separation prior to petroleomic analysis has not been exploited.

  This thesis explores the use of normal phase HPLC and FT-ICR MS to gain a better understanding of the nitrogen compounds found in gas oil samples derived from oil sands bitumen. Unconventional hypercrosslinked polystyrene stationary phases and a commercial dinitrophenyl (“DNAP”) stationary phase were studied for their nitrogen group-type separation capabilities. Hypercrosslinked polystyrene was found to have unique selectivity for nitrogen compounds. Custom synthesized hypercrosslinked polystyrene was able to separate pyrroles, pyridines and polycyclic aromatic hydrocarbons (PAHs) into three distinct groups, acting via an adsorption mechanism. Polymeric hypercrosslinked polystyrene separates model compounds by both aromaticity and heteroatom content. The “DNAP” column separates nitrogen-containing compounds from PAHs.

  Methods were developed in order to analyze HPLC fractions collected offline on an FT-ICR MS system. Concentrating the HPLC fractions and adding strong acid or base prior to analysis were important steps. Contamination from sample handling was found to be an issue, and proper procedures to eliminate sources of contamination are described, including a previously unreported interference from iron-formate ion clusters.

  These methods were used to analyze HPLC fractions of gas oil samples on “DNAP” on the FT-MS. The MS data revealed that the chromatographic peak intensity on “DNAP” can be correlated to nitrogen content in the sample, and that alkylation reduces retention of pyrroles and pyridines. “DNAP” separations can also be used to judge the relative efficiency of nitrogen removal processes. Comparison of fraction data to petroleomic analysis of unfractionated samples showed that the HPLC fraction analysis is a compliment to full petroleomic studies of samples.

• Subjects / Keywords

  • HPLC
  • Nitrogen
  • FT-ICR MS
  • Petroleum

• Graduation date

  Fall 2012

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R37X1Q

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.