Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry has recently revealed that petroleum crude oil contains heteroatom-containing (N,O,S) organic components having more than 20 000 distinct elemental compositions (CcHhNnOoSs). It is therefore now possible to contemplate the ultimate characterization of all of the chemical constituents of petroleum, along with their interactions and reactivity, a concept we denote as “petroleomics”. Such knowledge has already proved capable of distinguishing petroleum and its distillates according to their geochemical origin and maturity, distillation cut, extraction method, catalytic processing, etc. The key features that have opened up this new field have been (a) ultrahigh-resolution FT-ICR mass analysis, specifically, the capability to resolve species differing in elemental composition by C3 vs SH4 (i.e., 0.0034 Da); (b) higher magnetic field to cover the whole mass range at once; (c) dynamic range extension by external mass filtering; and ...

Petroleomics: The Next Grand Challenge for Chemical Analysis

Each different molecular elemental composition—e.g., CcHhNnOoSs—has a different exact mass. With sufficiently high mass resolving power (m/Δm50% ≈ 400,000, in which m is molecular mass and Δm50% is the mass spectral peak width at half-maximum peak height) and mass accuracy (<300 ppb) up to ≈800 Da, now routinely available from high-field (≥9.4 T) Fourier transform ion cyclotron resonance mass spectrometry, it is possible to resolve and identify uniquely and simultaneously each of the thousands of elemental compositions from the most complex natural organic mixtures, including petroleum crude oil. It is thus possible to separate and sort petroleum components according to their heteroatom class (NnOoSs), double bond equivalents (DBE = number of rings plus double bonds involving carbon, because each ring or double bond results in a loss of two hydrogen atoms), and carbon number. “Petroleomics” is the characterization of petroleum at the molecular level. From sufficiently complete characterization of the organic composition of petroleum and its products, it should be possible to correlate (and ultimately predict) their properties and behavior. Examples include molecular mass distribution, distillation profile, characterization of specific fractions without prior extraction or wet chemical separation from the original bulk material, biodegradation, maturity, water solubility (and oil:water emulsion behavior), deposits in oil wells and refineries, efficiency and specificity of catalytic hydroprocessing, “heavy ends” (asphaltenes) analysis, corrosion, etc.

https://www.pnas.org/content/pnas/105/47/18090.full.pdf

Petroleomics: Chemistry of the underworld

P2X receptors are ATP-gated ion channels in the plasma membrane, but activation of the P2X7 receptor also leads to rapid cytoskeletal re-arrangements such as membrane blebbing. We identified 11 proteins in human embryonic kidney cells that interact with the rat P2X7 receptor, by affinity purification followed by mass spectroscopy and immunoblotting [laminin α3, integrin β2, β-actin, α-actinin, supervillin, MAGuK, three heat shock proteins, phosphatidylinositol 4-kinase and receptor protein tyrosine phosphatase-β (RPTPβ)]. Activation of the P2X7 receptor resulted in its dephosphorylation. Whole-cell recordings from cells expressing P2X7 receptors showed that this markedly reduced subsequent ionic currents and it also slowed membrane bleb formation. By mutagenesis, we identified Tyr343 in the putative second transmembrane domain as the site of phosphorylation. Thus, we have identified a P2X7 receptor signalling complex, some members of which may initiate cytoskeletal rearrangements following receptor activation. Others, such as RPTPβ, might exert feedback control of the channel itself through its dephosphorylation.

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Proteomic and functional evidence for a P2X7 receptor signalling complex

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/Δm50% ≈ 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 heteroa...

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

Milestones in fourier transform ion cyclotron resonance mass spectrometry technique development

The ultrahigh-resolution capabilities of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) have been demonstrated for accurate mass measurements of complex hydrocarbon mixtures. Ultrahigh resolution is achievable over a wide mass range by the use of stored waveform inverse Fourier transform (SWIFT) ejection to eliminate space-charge effects. The mass measurement stability under different ionization conditions eliminates the need of mass reference standards during acquisition of sample spectra, thereby increasing sensitivity of the accurate mass measurements under low-voltage electron ionization conditions. 27 refs., 4 figs., 2 tabs.

Chang Samuel. Hsu

Papers

Hydrocarbon Characterization by UltraHigh Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry