Desorption/ionization fluence thresholds and improved mass spectral consistency measured using a flattop laser profile in the bioaerosol mass spectrometry of single Bacillus endospores

Paul T. Steele, Abneesh Srivastava, Maurice E. Pitesky, David P. Fergenson, Herbert J. Tobias, Eric E. Gard, Matthias Frank

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

Bioaerosol mass spectrometry is being developed to analyze and identify biological aerosols in real time. Mass spectra of individual Bacillus endospores were measured with a bipolar aerosol time-of-flight mass spectrometer in which molecular desorption and ionization were produced using a single laser pulse from a Q-switched, frequency-quadrupled Nd:YAG laser that was modified to have an approximately flattop profile. The flattened laser profile allowed the minimum fluence required to desorb and ionize significant numbers of ions from single aerosol particles to be determined. For Bacillus spores, this threshold had a mean value of ∼1 nJ/μm2 (0.1 J/cm2). Thresholds for individual spores, however, could apparently deviate by 20% or more from the mean. Threshold distributions for clumps of MS2 bacteriophage and bovine serum albumin were subsequently determined. Finally, the flattened profile was observed to increase the reproducibility of single-spore mass spectra. This is consistent with the general conclusions of our earlier paper on the fluence dependence of single-spore mass spectra and is particularly significant because it is expected to enable more robust differentiation and identification of single bioaerosol particles.

Original languageEnglish (US)
Pages (from-to)7448-7454
Number of pages7
JournalAnalytical Chemistry
Volume77
Issue number22
DOIs
StatePublished - Nov 15 2005
Externally publishedYes

ASJC Scopus subject areas

  • Analytical Chemistry

Fingerprint Dive into the research topics of 'Desorption/ionization fluence thresholds and improved mass spectral consistency measured using a flattop laser profile in the bioaerosol mass spectrometry of single Bacillus endospores'. Together they form a unique fingerprint.

  • Cite this