A New Matrix Assisted Ionization Method for the Analysis of Volatile and Nonvolatile Compounds by Atmospheric Probe Mass Spectrometry

  • Shubhashis Chakrabarty
  • Vincent S. Pagnotti
  • Ellen D. Inutan
  • Sarah Trimpin
  • Charles N. McEwen
Research Article


Matrix assisted ionization of nonvolatile compounds is shown not to be limited to vacuum conditions and does not require a laser. Simply placing a solution of analyte dissolved with a suitable matrix such as 3-nitrobenzonitrile (3-NBN) or 2,5-dihydroxyacetophenone on a melting point tube and gently heating the dried sample near the ion entrance aperture of a mass spectrometer using a flow of gas produces abundant ions of peptides, small proteins, drugs, and polar lipids. Fundamental studies point to matrix-mediated ionization occurring prior to the entrance aperture of the mass spectrometer. The method is analytically useful, producing peptide mass fingerprints of bovine serum albumin tryptic digest consuming sub-picomoles of sample. Application of 100 fmol of angiotensin I in 3-NBN matrix produces the doubly and triply protonated molecular ions as the most abundant peaks in the mass spectrum. No carryover is observed for samples containing up to 100 pmol of this peptide. A commercial atmospheric samples analysis probe provides a simple method for sample introduction to an atmospheric pressure ion source for analysis of volatile and nonvolatile compounds without using the corona discharge but using sample preparation similar to matrix-assisted laser desorption/ionization.

Key words

Nonvolatile compounds Peptides Drugs Lipids Mass spectrometry Matrix assisted Probe introduction 

Supplementary material

13361_2013_634_MOESM1_ESM.doc (1.5 mb)
Supporting InformationFigures showing mass spectra of bradykinin using 3-NBN, 2,5-DHAP, and 2,5-DHB, and angiotensin I, insulin, sphingomyelin, verapamil, hydroxycortisone, and hydroxychloroquine using 3-NBN with ASAP probe introduction are presented along with mass spectra of levofloxacin, ubiquitin, myoglobin, and saliva using 3-NBN and a voltage applied to the HESI probe. The mass spectrum of bradykinin using a Waters Xevo TQ-S mass spectrometer without an ASAP probe is also provided. (DOC 1513 kb)


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Copyright information

© American Society for Mass Spectrometry 2013

Authors and Affiliations

  • Shubhashis Chakrabarty
    • 1
  • Vincent S. Pagnotti
    • 1
  • Ellen D. Inutan
    • 2
  • Sarah Trimpin
    • 2
  • Charles N. McEwen
    • 1
  1. 1.University of the SciencesPhiladelphiaUSA
  2. 2.Wayne State UniversityDetroitUSA

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