Orbitrap Mass Spectrometry: A Proposal for Routine Analysis of Nonvolatile Components of Petroleum

Abstract

High-resolution mass spectrometry can provide a detailed fingerprint of the composition of the nonvolatile fraction of petroleum. That analysis is typically performed using Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry, which offers greater mass resolution than any other mass analyzer. While high resolution is desirable for complex mixtures, such as petroleum, the high costs associated with FT-ICR limit its use to a small number of research laboratories, limiting the impact of the measurement relative to more accessible techniques. Here, we explore whether there is a role for other high-resolution mass analyzers to complement FT-ICR. One such high-resolution mass analyzer is the LTQ Orbitrap XL, which presents significantly lower costs relative to typical FT-ICR instruments. The Orbitrap mass analyzer provides mass resolution inferior to the modern FT-ICR instrument but still sufficient to assign molecular formulas to individual components present in mixtures, especially those components present in relatively high abundance. Indeed, the resolution of the LTQ Orbitrap XL is comparable to that obtained by FT-ICR instruments 1 decade ago, at which time FT-ICR was being used successfully to fingerprint petroleum. Here, we demonstrate successful application of the Orbitrap to resolve and identify >1000 of the more abundant molecular formulas in the negative ion electrospray ionization mass spectrum of a petroleum sample. These results are compared to the 9.4 T FT-ICR analysis of the same sample (published previously; Pomerantz, A. E.; Ventura, G. T.; McKenna, A. M.; Cañas, J.; Auman, J.; Koerner, K.; Curry, D.; Nelson, R. K.; Reddy, C. M.; Rodgers, R. P.; Marshall, A. G.; Peters, K. E.; Mullins, O. C. Combining biomarker and bulk compositional gradient analysis to assess reservoir connectivity. Org. Geochem. 2010, 41, 812À821), and in this analysis, both the compositional fingerprints and conclusions derived from those fingerprints are essentially the same for the FT-ICR and Orbitrap data. Setting up and operating a LTQ Orbitrap XL mass spectrometer presents significantly lower initial and continuing costs compared to setting up and operating a 9.4 T FT-ICR, and this difference may make the Orbitrap accessible to laboratories for which FT-ICR is cost-prohibitive. Although several valuable high-resolution mass spectrometric analyses require the extremely high resolution of FT-ICR, we propose Orbitrap mass spectrometry as a method for routine analysis of the composition of the more abundant species in the nonvolatile and polar fraction of petroleum. Extending the realm of high-resolution mass spectrometry from a limited research environment to routine analysis would increase the utility of the technique and the impact of fundamental research regarding mass spectrometry of petroleum.

Molecular characterization of heteroatomic compounds in a high-temperature coal tar using three mass spectrometers

“…Although the resolving power of quadrupole mass analyzer in GC/MS is much lower than that of TOF and Orbitrap, the fragmentation patterns induced by a highly energetic process in the ion source of GC/MS can facilitate accurate determination of structural features of the compounds [29]. TOF and Orbitrap provide high and ultrahigh resolving power, respectively, for accurate mass measurement to assign elemental compositions of fossil fuels [30,31]. Compared to TOF, Orbitrap is a relatively new mass analyzer commercialized by Thermo-Fisher Scientific as a part of hybrid LTQ Orbitrap instrument in 2005 [32].…”

Characterization of anti-theft devices directly from the surface of banknotes via easy ambient sonic spray ionization mass spectrometry

“…The advantages of Orbitrap MS include a fast scan rate coupled to ultra high resolution and accuracy measurements [27,28] and higher-energy collision dissociations (HCDs), making it a powerful tool in forensic investigations [29].…”

Characterization of Acidic Compounds in Brazilian Tar Sand Bitumens by LTQ Orbitrap XL: Assessing Biodegradation Using Petroleomics

“…27,28 Both of the high-resolution mass spectrometers discussed above have emerged as invaluable tools in analyzing the chemical composition of petroleum. 29,30 Because each molecule has a distinct elemental composition, e.g., C c H h N n O o S s , has a unique exact mass, sufficiently high mass-resolving power and mass accuracy make it possible to simultaneously resolve and identify each of the thousands of compounds found in petroleum. Additionally, it is possible to separate and classify petroleum components according to their heteroatom class (N n O o S s ), double bond equivalent (DBE), and carbon number.…”

“…The LTQ Orbitrap XL presents lower costs relative to typical FT ICR instruments, but it still retains sufficient resolution to assign molecular formulas to individual components present in mixtures, mainly those of relatively high abundance. 29,30 In this context, the influence of biodegradation on the acidic species composition was explored by O 2 species distribution, DBEs, and A/C ratios. …”

“…Pomerantz et al 29 have already used this alternative technique to analyze whole oil, proposing the Orbitrap as method for routine analysis of the composition of the more abundant compounds in the polar fraction of petroleum. However, the analysis of acidic fraction instead the whole oil improves the MS analysis by avoiding unresolved compounds due to limited resolution of standard Orbitrap.…”