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Utility of Three Types of Mass Spectrometers for Determining Elemental Compositions of Ions Formed from Chromatographically Separated Compounds

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Abstract:Sponsor Referee: Douglas F. Barofsky, Oregon State University Concentration factors of 1000 and more reveal dozens of compounds in extracts of water supplies. Library mass spectra for most of these compounds are not available, and alternative means of identification are needed. Determination of the elemental compositions of the ions in mass spectra makes feasible searches of commercial and chemical literature that often lead to compound identification. Instrumental capabilities that constrain the utility of a mass spectrometer for determining ion compositions for compounds that elute from a chromatographic column are scan speed, mass accuracy, linear dynamic range, and resolving power. Mass Peak Profiling from Selected Ion Recording Data (MPPSIRD) performed with a double focusing mass spectrometer provides the best combination of these capabilities. This technique provides unique ion compositions for higher mass ions than data acquired with orthogonal acceleration time-of- flight (oa-TOF) or Fourier transform ion cyclotron resonance mass spectrometers. Multiple compositions are usually possible for an ion with a mass exceeding 150 Da within the error limits of the mass measurement. The correct composition is selected based on measured exact masses of the profiles higher in mass by I and 2 Da and accurate
measurement of the summed abundances of the isotopic ions contributing to these two profiles relative to the monoisotopic ion. A Profile Generation Model (PGM) automatically determines which compositions are consistent with measured exact masses and relative abundances. The utility of oa-TOF and double focusing mass spectrometry using Ion Composition Elucidation (MPPSIRD plus the PGM) are considered for determining ion compositions of two compounds found in drinking water extracts and a third compound from a monitoring well at a landfill.
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Citation:Grange, A. H., F. A. Genicola, and G. W. Sovocool. Utility of Three Types of Mass Spectrometers for Determining Elemental Compositions of Ions Formed from Chromatographically Separated Compounds. RAPID COMMUNICATIONS IN MASS SPECTROMETRY 16(24):2356-2369, (2002).
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Contact: Chris Siebert - (702) 798-2234 or siebert.christopher@epa.gov
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Division: Environmental Sciences Division
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Branch: Environmental Chemistry Branch
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Product Type: Journal
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Published: 11/20/2002
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Related Entries:
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Bullet Item Advances in Sampling, Separation, Detection and Identification That Address Unmet Needs of Oswer and the Regions
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