Mass spectrometric separation and quantitation of overlapping isotopologues. H2O/HOD/D2O and H2Se/HDSe/D2Se mixtures

J Am Soc Mass Spectrom. 2006 Jul;17(7):1028-36. doi: 10.1016/j.jasms.2006.02.008. Epub 2006 May 19.

Abstract

Three conceptually different mathematical methods are presented for accurate mass spectrometric determination of H2O/HOD/D2O and H2Se/HDSe/D2Se concentrations from mixtures. These are alternating least-squares, weighted two-band target entropy minimization, and a statistical mass balance model. The otherwise nonmeasurable mass spectra of partially deuterated isotopologues (HOD and HDSe) are mathematically constructed. Any recorded isotopologue mixture mass spectra are then deconvoluted by least-squares into their components. This approach is used to study the H2O/D2O exchange reaction, and is externally validated gravimetrically. The H2O/D2O exchange equilibrium constant is also measured from the deconvoluted 70 eV electron impact GC/MS data (K = 3.85 +/- 0.03).

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms*
  • Complex Mixtures / analysis*
  • Data Interpretation, Statistical
  • Deuterium Exchange Measurement / methods*
  • Deuterium Oxide / analysis*
  • Isotope Labeling / methods
  • Mass Spectrometry / methods*
  • Selenium Compounds / analysis*
  • Water / analysis*

Substances

  • Complex Mixtures
  • Selenium Compounds
  • Water
  • Deuterium Oxide
  • hydrogen selenide