Discrimination between bacterial spore types using time-of-flight mass spectrometry and matrix-free infrared laser desorption and ionization

J. N. Ullom, Matthias Frank, E. E. Gard, J. M. Horn, S. E. Labov, K. Langry, F. Magnotta, K. A. Stanion, C. A. Hack, W. H. Benner

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

We demonstrate that molecular ions with mass-to-charge ratios (m/z) ranging from a few hundred to 19 050 can be desorbed from whole bacterial spores using infrared laser desorption and no chemical matrix. We have measured the mass of these ions using time-of-flight mass spectrometry and we observe that different ions are desorbed from spores of Bacillus cereus, Bacillus thuringiensis, Bacillus subtilis, and Bacillus niger. Our results raise the possibility of identifying microorganisms using mass spectrometry without conventional sample preparation techniques such as the addition of a matrix. We have measured the dependence of the ion yield from B. subtilis on desorption wavelength over the range 3.05-3.8 μm, and we observe the best results at 3.05 μm. We have also generated mass spectra from whole spores using 337-nm ultraviolet laser desorption, and we find that these spectra are inferior to spectra generated with infrared desorption. Since aerosol analysis is a natural application for matrix-free desorption, we have measured mass spectra from materials such as ragweed pollen and road dust that are likely to form a background to microbial aerosols. We find that these materials are readily differentiated from bacterial spores.

Original languageEnglish (US)
Pages (from-to)2331-2337
Number of pages7
JournalAnalytical Chemistry
Volume73
Issue number10
DOIs
StatePublished - May 15 2001
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry

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    Ullom, J. N., Frank, M., Gard, E. E., Horn, J. M., Labov, S. E., Langry, K., Magnotta, F., Stanion, K. A., Hack, C. A., & Benner, W. H. (2001). Discrimination between bacterial spore types using time-of-flight mass spectrometry and matrix-free infrared laser desorption and ionization. Analytical Chemistry, 73(10), 2331-2337. https://doi.org/10.1021/ac001551a