Reading Chemical Fine Print:  Resolution and Identification of 3000 Nitrogen-Containing Aromatic Compounds from a Single Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrum of Heavy Petroleum Crude Oil

Abstract

Extra heavy petroleum crude oil (50% of the mixture boils at >566 °C) has been analyzed directly, without prior fractionation, by a high-field (9.4 T) Fourier transform ion cyclotron resonance mass spectrometer coupled to an external micro-electrospray ion source. At an average mass resolving power, (m/Δm 50% ≈ 50 000), a single wideband (250−1250 Da) mass spectrum exhibited ∼5000 resolved peaks with an average mass of 617 Da (e.g., up to 7−10 resolved peaks at each nominal mass). Their elemental compositions were positively identified by accurate mass measurement with an average deviation of less than 1 mDa from each assigned elemental composition. The number of elemental compositions at each nominal mass, the number of sulfur/oxygen atoms in a molecule, and aromaticity each increase with increasing mass. On the basis of elemental composition alone, we resolve more than 3000 distinct chemical formulas (excluding 13C isotopic species). Of the 3000 unique elemental compositions, we identify 12 major heteroatomic “classes”; (e.g., molecules containing N, NS, NS2, NO, NOS, etc.); for the various “classes”, we identify more than 100 hydrocarbon “types” (e.g., molecules with the same number of rings plus double bonds); and for each “type”, we determine the carbon number distribution (20−80 carbons) to reveal the number of alkyl carbons appended to aromatic rings. The present results represent the most complete chemical characterization ever achieved for such a complex mixture, based on a single experimental data set.

Petroleomics: MS Returns to Its Roots.

“…Another seminal series of reports, by Boduszynski and others, on the composition of heavy petroleum drew on a variety of analytical techniques to derive a surprisingly inclusive description of complex petrochemicals (8)(9)(10)(11). The high mass resolution and high mass accuracy of FT ion cyclotron resonance (FTICR) MS made it an attractive candidate for complex mixture analysis when it made its debut in the mid-1970s, although those capabilities were fully realized only in the last decade or so (12)(13)(14). These strengths and the rapid development of computer technology now promise to make petroleomics feasible.…”

Top-down identification and characterization of biomolecules by mass spectrometry

“…Although the amazingly high resolving power and MS/MS capabilities of FTMS have made possible exciting new applications for characterizing complex petroleum samples [96], the great majority of the ~575 FTMS instruments now available are in proteomics laboratories. Most of these instruments are producing uniquely useful research and protein characterization data, yet relatively few are used in extensive top-down applications, especially those with automated introduction of separated (e.g., LC, CE) fractions of complex protein mixtures, online data reduction to select molecular ions for CAD or ECD, direct PTM characterization, etc.…”

Thermochemical Sulfate Reduction Simulation Experiments on the Formation and Distribution of Organic Sulfur Compounds in the Tuha Crude Oil

“…[15][16][17][18][19] The samples were analyzed using a Bruker apex-ultra FT-ICR MS equipped with a 9.4T actively shielded superconducting magnet is used to analyze the samples. The operating conditions for positive ion formation were −3.0 kV emitter voltage, −3.5 kV capillary entrance voltage, and 320 V capillary column end voltage.…”