Computer assignment of elemental compositions of mass spectral peaks from isotopic abundances

ABSTRACT We report the first resolution, identification, and characterization of nickel and vanadyl porphyrins simultaneously in weathered oil samples derived from natural seeps in Southern California. Atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolving power (m/Δm50% > 1,000,000 at m/z 500) and sub-ppm mass error (<50 ppb) required to identify nickel porphyrin isotopes for unambiguous elemental composition assignment. We also report the first simultaneous identification and categorization of both vanadyl and nickel porphyrins in the same sample, without prior sample fractionation. More than 85,000 mass spectral peaks are resolved and identified in a single mass spectrum, and represent the most extensive molecular deconvolution of an organic mixture characterized to date.

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Molecular weight parity predicted from the parity values of mass spectral peaks

Organic Mass Spectrometry ◽

10.1002/oms.1210160207 ◽

1981 ◽

Vol 16 (2) ◽

pp. 82-84 ◽

Cited By ~ 2

Author(s):

In Ki Mun ◽

Rengachari Venkataraghavan ◽

Fred W. McLafferty

Keyword(s):

Molecular Weight ◽

Mass Spectral ◽

Spectral Peaks

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Asymmetrical features of mass spectral peaks produced by quadrupole mass filters

Rapid Communications in Mass Spectrometry ◽

10.1002/rcm.1017 ◽

2003 ◽

Vol 17 (10) ◽

pp. 1051-1055 ◽

Cited By ~ 15

Author(s):

John Raymond Gibson ◽

Stephen Taylor

Keyword(s):

Quadrupole Mass ◽

Mass Spectral ◽

Spectral Peaks ◽

Quadrupole Mass Filters

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Mass Peak Profiling from Selected-Ion Recording Data as a Tool for Regulatory Analyses

Journal of AOAC International ◽

10.1093/jaoac/82.6.1443 ◽

1999 ◽

Vol 82 (6) ◽

pp. 1443-1457 ◽

Cited By ~ 2

Author(s):

Andrew H Grange ◽

G Wayne Sovocool

Keyword(s):

High Resolution Mass Spectrometry ◽

High Mass ◽

Generation Model ◽

Mass Peak ◽

Exact Mass ◽

Temporal Separation ◽

Molecular Ion ◽

Mass Spectral ◽

Elemental Compositions ◽

Fragment Ions

Abstract Identification of compounds in mixtures of environmental contaminants or synthetic products is essential for regulatory analyses. Exact masses of ions determined by high resolution mass spectrometry provide unique elemental compositions only for low-mass ions (<150 Da). Using mass peak profiling from selected-ion recording data (MPPSIRD) to acquire additional mass spectral data and a profile generation model (PGM) for automated interpretation of the data, provides elemental compositions for ions with m/z up to 600, based on incontestable properties of atoms, their exact masses, isotopic abundances, and valences. In this study, MPPSIRD and a PGM were used to identify intended and unintended products resulting from attempted syntheses of 2 thermolabile, nonionic, phosphorothioate compounds. The products were volatilized from a probe inserted into a VG70-250SE double-focusing mass spectrometer. High mass resolution substituted separation in the mass domain for the temporal separation of most components provided by chromatographic techniques. MPPSIRD and the PGM identified the correct composition for M+• by rejecting all other compositions that were possible within the error limits of the exact mass determinations for M+• MPPSIRD was used with 10 000-24 000 resolution to determine exact masses of ions prominent in mass spectra and to isolate signals from different ions with the same nominal mass. Superposition of volatilization peaks of ions and linked scans (constant magnetic field to electrostatic sector voltage ratio) correlated fragment ions with the molecular ion. The PGM determined the compositions of fragment ions, using the number of atoms of each element in the molecular ion as limits. Fragmentation schemes based on these ions and the tables of exact masses and relative abundances provided a preponderance of evidence for the product identities.

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Donor-atom effects in the mass spectra of complexes of dipivaloylmethane and its monothio and dithio analogues

Australian Journal of Chemistry ◽

10.1071/ch9760257 ◽

1976 ◽

Vol 29 (2) ◽

pp. 257 ◽

Cited By ~ 5

Author(s):

CG Macdonald ◽

RL Martin ◽

AF Masters

Keyword(s):

Mass Spectra ◽

Mixed Ligand ◽

Donor Atom ◽

Mass Spectral ◽

Fragment Ions ◽

Nickel Compounds ◽

Spectral Peaks ◽

Electron Impact Mass ◽

Ligand Species ◽

Impact Mass

The progressive replacement by sulphur in the isostructural planar nickel compounds bis(2,2,6,6- tetramethylheptane-3,5-dionato)nickel(11) (1), bis(2,2,6,6-tetramethyl-5-thioxoheptan-3-onato)nickel(11) (2) and bis(2,2,6,6-tetramethylheptane-3,5-dithionato)nickel(11) (3) causes a change in their positive electron impact mass spectra from one dominated by metal-containing fragment ions (1) to one But 1 dominated by oxidized ligands (3). Comparisons are also made with the spectra of tris(monothio-dipivaloylmethanato)cobalt(111) and bis(1,l,1-trifluoro-4-thioxopentan-2-onato)nickel (11). Mass spectral peaks corresponding to mixed ligand species were observed when mixtures of (1) and (2) were vaporized in the mass spectrometer.

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