University of Warwick crest Dr. Mark P. Barrow: Research in mass spectrometry

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Petroleomics

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FT-ICR mass spectrum of an oil extract

12 T solariX FTICR at the University of Warwick. Hover your cursor over the image for an magnified view.

APPI FT-ICR mass spectrum of oil sands process water

A broadband APPI FT-ICR mass spectrum of oil sands process water. Hover your cursor over the image for an magnified view.

Enlarged region of the APPI FT-ICR mass spectrum of oil sands process water

An enlarged region of the mass spectrum shown above, highlighting the ultra-high resolving power and mass accuracy associated with FT-ICR mass spectrometry. Hover your cursor over the image for an magnified view.

Plot of different naphthenic acid species in an oil extract

An example plot of the different naphthenic acid species present in a crude oil extract, shown as relative intensity versus carbon number. Hover your cursor over the image for an magnified view.

Petroleum

Petroleum-related samples, such as crude oils, are highly complex mixtures and typically contain thouands of components. Analysis of such mixtures using mass spectrometric methods has been termed "petroleomics," and can prove problematic. Any instrument employed for the task would require ultra-high resolving power and mass accuracy. The type of mass spectrometer most associated with such characteristics is the Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. For petroleum-related research at the University of Warwick, a 9.4 T Bruker BioAPEX II FT-ICR mass spectrometer and, more recently, a 12 T Bruker solariX instrument have been used.

A wide range of petroleum-related samples can be analyzed, including crude oils, crude oil extracts, and fuels, amongst others. Electrospray ionization (ESI), or a derivative such as nanospray, and atmospheric pressure photoionization (APPI) are typically used as the ionization methods of first choice, depending upon requirements. Both techniques are relatively soft ionization methods and thus minimize fragmentation. ESI is more suitable for ionic and highly polar compounds, while APPI can be used for characterizing less polar compounds which are not observed using ESI (e.g. less polar, sulfur-containing species). The ultra-high resolving power and mass accuracy (sub-ppm) associated with FT-ICR mass spectrometry afford a high degree of confidence in the mass assignments, and therefore the technique is well-suited to the analysis of complex mixtures such as petroleum-related samples.

Naphthenic acids

Naphthenic acids are one such class of compound found within crude oils and have the empirical formula: CnH2n+ZO2, where Z is a negative value and is frequently referred to as the "hydrogen deficiency." Such species can cause corrosion in refinery equipment, resulting in costs that are ultimately passed on to the consumer, and the corrosiveness of the acids is believed to be linked to their size and structure.

The total acid number (TAN) of an oil, defined as the number of milligrams of potassium hydroxide required to neutralize one gram of crude oil, has always been believed to be indicative of the naphthenic acid content, but it is increasingly being accepted that the TAN of an oil is not such a reliable guide. A new method for characterizing the naphthenic acid content of crude oils is therefore highly desirable. In addition to the potential corrosiveness, naphthenic acids are also known to be toxic to a range of aquatic organisms. Environmental regulators too, consequently, have an interest in characterization of naphthenic acids in water samples, and the oil industry has additional concerns about how to dispose of the unwanted acids. Work performed at the University of Warwick has demonstrated the naphthenic acid profiles can act as fingerprints for different oilfields.

Related references:

  1. “Preliminary fingerprinting of Athabasca oil sands polar organics in environmental samples using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry,” John V. Headley, Mark P. Barrow, Kerry M. Peru, Brian Fahlman, Richard A. Frank, Gregory Bickerton, Mark E. McMaster, Joanne Parrott, and L. Mark Hewitt, Rapid Commun. Mass Spectrom., 2011, 25, pp. 1899-1909
  2. “Combined Influence of Salinity and Solvent Effects on the Characterization of Naphthenic Acids from Athabasca Oil Sands Using Electrospray Ionization,” John V. Headley, Mark P. Barrow, Kerry M. Peru, and Peter J. Derrick, J. Environ. Science and Health, Part A, 2011, 46, pp. 844-854
  3. “Petroleomics: study of the old and the new,” Mark P. Barrow, Biofuels, 2010, 1, pp. 651-655 (Invited editorial)
  4. “Athabasca oil sands process water: characterization by atmospheric pressure photoionization and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry,” Mark P. Barrow, Matthias Witt, John V. Headley, and Kerry M. Peru, Anal. Chem., 2010, 82, pp. 3727-3735
  5. “Characterization of Naphthenic Acid Singly Charged Noncovalent Dimers and Their Dependence on the Accumulation Time within a Hexapole in Fourier Transform Ion Cyclotron Resonance Mass Spectrometry,” Raffaello Da Campo, Mark P. Barrow, Andrew G. Shepherd, Malcolm Salisbury, and Peter J. Derrick, Energy Fuels, 2009, 23, pp. 5544-5549
  6. “Data Visualization for the Characterization of Naphthenic Acids within Petroleum Samples,” Mark P. Barrow, John V. Headley, Kerry M. Peru, and Peter J. Derrick, Energy Fuels, 2009, 23, pp. 2592-2599
  7. “Mass Spectrometric Characterization of Naphthenic Acids in Environmental Samples: A Review,” John V. Headley, Kerry M. Peru, and Mark P. Barrow, Mass Spectrom. Rev., 2009, 28, pp. 121-134
  8. “Analysis of naphthenic acids from Athabasca oil sands using Fourier transform ion cyclotron resonance mass spectrometry,” Mark P. Barrow, Kerry M. Peru, John V. Headley, and Peter J. Derrick, 30th Annual Meeting of the British Mass Spectrometry Society, University of York, September 7th - 10th, 2008
  9. “Characterization of naphthenic acids from Athabasca oil sands for environmental analysis using Fourier transform ion cyclotron resonance mass spectrometry,” Mark P. Barrow, Kerry M. Peru, John V. Headley, and Peter J. Derrick, 56th ASMS Conference on Mass Spectrometry, Denver, Colorado, June 1st - 5th, 2008
  10. “Characterization of Naphthenic Acids from Athabasca Oil Sands Using Electrospray Ionization: The Significant Influence of Solvents,” John V. Headley, Kerry M. Peru, Mark P. Barrow, and Peter J. Derrick, Anal. Chem., 2007, 79, pp. 6222-6229
  11. “Solvent Effects During Characterization of Naphthenic Acid Mixtures Using Nanospray Fourier Transform Ion Cyclotron Resonance Mass Spectrometry,” Mark P. Barrow, Kerry M. Peru, John V. Headley, and Peter J. Derrick, 55th ASMS Conference on Mass Spectrometry, Indianapolis, Indiana, June 3rd - 7th, 2007
  12. “Aggregation of Naphthenic Acids Studied by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry,” Raffaello Da Campo, Mark P. Barrow, Malcolm Salisbury, Andrew Shepherd, and Peter J. Derrick, 55th ASMS Conference on Mass Spectrometry, Indianapolis, Indiana, June 3rd - 7th, 2007
  13. "Solvent Effects in Electrospray Ionization of Naphthenic Acids From Athabasca Oil Sands," John V Headley, Kerry M. Peru, Mark P. Barrow, and Peter J. Derrick, 55th ASMS Conference on Mass Spectrometry, Indianapolis, Indiana, June 3rd - 7th, 2007
  14. “Principles of Fourier transform ion cyclotron resonance mass spectrometry and its application in structural biology,” Mark P. Barrow, William I. Burkitt, and Peter J. Derrick, Analyst, 2005, 130, pp. 18-28
  15. "Fourier transform ion cyclotron resonance mass spectrometry of principal components in oilsands naphthenic acids," Mark P. Barrow, John V. Headley, Kerry M. Peru, and Peter J. Derrick, J. Chrom. A, 2004, 1058, pp. 51-59
  16. "Nanospray Ionization and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry for the Characterization of Naphthenic Acids with Respect to Environmental Analysis," Mark P. Barrow, John V. Headley, Kerry M. Peru, and Peter J. Derrick, 27th Annual Meeting of the British Mass Spectrometry Society, University of Derby, September 5th - 8th, 2004
  17. "Characterization of Naphthenic Acids For Environmental Analysis Using Nanospray Ionization and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry," Mark P. Barrow, John V. Headley, Kerry M. Peru, Pascal Manuelli, Bernard Escoffier, and Peter J. Derrick, 52nd ASMS Conference on Mass Spectrometry, Nashville, Tennessee, May 23rd - 27th, 2004
  18. "Investigating Corrosion through the Characterization of the Naphthenic Acid Content of Crude Oils Using Negative-Ion Nanospray Fourier Transform Ion Cyclotron Resonance Mass Spectrometry," Mark P. Barrow, Liam A. McDonnell, Xidong Feng, Jérémie Walker, Pascal Manuelli, and Peter J. Derrick, 16th International Mass Spectrometry Conference, Edinburgh International Conference Centre, August 31st - September 5th, 2003
  19. “Determination of the Nature of Naphthenic Acids Present in Crude Oils Using Nanospray Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: The Continued Battle Against Corrosion,” Mark P. Barrow, Liam A. McDonnell, Xidong Feng, Jérémie Walker, and Peter J. Derrick, Anal. Chem., 2003, 75, pp. 860-866
  20. “Investigating Corrosion, Calcium Deposition, and Emulsion Formation through the Characterization of the Naphthenic Acid Content of Crude Oils Using Negative-Ion Nanospray Fourier Transform Ion Cyclotron Resonance Mass Spectrometry,” Mark P. Barrow, Liam A. McDonnell, Xidong Feng, Jérémie Walker, Peter J. Derrick, 26th Annual Meeting of the British Mass Spectrometry Society, University of Loughborough, September 8th - 11th, 2002