title: Deprotonation effect of tetrahydrofuran-2-carbonitrile buffer gas dopant in ion mobility spectrometry.
abstract: When dopants are introduced into the buffer gas of an ion mobility spectrometer, spectra are simplified due to charge competition.
  
  
  
  We used electrospray ionization to inject tetrahydrofuran-2-carbonitrile (F, 2-furonitrile or 2-furancarbonitrile) as a buffer gas dopant into an ion mobility spectrometer coupled to a quadrupole mass spectrometer. Density functional theory was used for theoretical calculations of dopant-ion interaction energies and proton affinities, using the hybrid functional X3LYP/6-311++(d,p) with the Gaussian 09 program that accounts for the basis set superposition error; analytes structures and theoretical calculations with Gaussian were used to explain the behavior of the analytes upon interaction with F.
  
  
  
  When F was used as a dopant at concentrations below 1.5 mmol m(-3) in the buffer gas, ions were not observed for α-amino acids due to charge competition with the dopant; this deprotonation capability arises from the production of a dimer with a high formation energy that stabilized the positive charge and created steric hindrance that deterred the equilibrium with analyte ions. F could not completely strip other compounds of their charge because they either showed steric hindrance at the charge site that deterred the approach of the dopant (2,4-lutidine, and DTBP), formed intramolecular bonds that stabilized the positive charge (atenolol), had high proton affinity (2,4-lutidine, DTBP, valinol and atenolol), or were inherently ionic (tetraalkylammonium ions).
  
  
  
  This selective deprotonation suggests the use of F to simplify spectra of complex mixtures in ion mobility and mass spectrometry in metabolomics, proteomics and other studies that generate complex spectra with thousands of peaks. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Universidad de Cartagena, Campus de San Pablo, Programa de Química, Cartagena, Colombia.
authors.forename: Roberto
authors.initials: R
authors.lastname: Fernandez-Maestre
authors.affiliation: Universidad de Cartagena, Campus de San Pablo, Programa de Química, Cartagena, Colombia.
authors.forename: Dairo
authors.initials: D
authors.lastname: Meza-Morelos
authors.affiliation: Excellims Corporation, 20 Main Street, Acton, MA, USA.
authors.forename: Ching
authors.initials: C
authors.lastname: Wu