Parameters contributing to efficient ion generation in aerosol MALDI mass spectrometry

  • Erica L. McJimpsey
  • William M. Jackson
  • Carlito B. Lebrilla
  • Herbert Tobias
  • Michael J. Bogan
  • Eric E. Gard
  • Matthias Frank
  • Paul T. Steele
Articles

DOI: 10.1016/j.jasms.2007.11.009

Cite this article as:
McJimpsey, E.L., Jackson, W.M., Lebrilla, C.B. et al. J. Am. Soc. Spectrom. (2008) 19: 315. doi:10.1016/j.jasms.2007.11.009

Abstract

The Bioaerosol Mass Spectrometry (BAMS) system was developed for the real-time detection and identification of biological aerosols using laser desorption ionization. Greater differentiation of particle types is desired; consequently MALDI techniques are being investigated. The small sample size (∼1 μm3), lack of substrate, and ability to simultaneously monitor both positive and negative ions provide a unique opportunity to gain new insight into the MALDI process. Several parameters known to influence MALDI molecular ion yield and formation are investigated here in the single particle phase. A comparative study of five matrices (2,6-dihydroxyacetophenone, 2,5-dihydroxybenzoic acid, α-cyano-4-hydroxycinnamic acid, ferulic acid, and sinapinic acid) with a single analyte (angiotensin I) is presented and reveals effects of matrix selection, matrix-to-analyte molar ratio, and aerosol particle diameter. The strongest analyte ion signal is found at a matrix-to-analyte molar ratio of 100:1. At this ratio, the matrices yielding the least and greatest analyte molecular ion formation are ferulic acid and α-cyano-4-hydroxycinnamic acid, respectively. Additionally, a significant positive correlation is found between aerodynamic particle diameter and analyte molecular ion yield for all matrices. SEM imaging of select aerosol particle types reveals interesting surface morphology and structure.

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Copyright information

© American Society for Mass Spectrometry 2008

Authors and Affiliations

  • Erica L. McJimpsey
    • 1
    • 2
  • William M. Jackson
    • 1
  • Carlito B. Lebrilla
    • 1
  • Herbert Tobias
    • 2
  • Michael J. Bogan
    • 2
  • Eric E. Gard
    • 2
  • Matthias Frank
    • 2
  • Paul T. Steele
    • 2
  1. 1.Department of ChemistryUniversity of California, DavisDavisUSA
  2. 2.Lawrence Livermore National LaboratoryLivermoreUSA

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