Application of matrix-assisted laser desorption/ionization to on-line aerosol time-of-flight mass spectrometry

Abstract

Matrix-assisted laser desorption/ionization (MALDI) mass spectra were obtained from single biological aerosol particles using an aerosol time-of-flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed the aerosol to be coated with matrix material as the sampled stream entered the spectrometer. Mass spectra were generated from aerosol composed either of gramicidin-S or erythromycin, two small biological molecules, or from aerosolised spores of Bacillus subtilis var niger. Three different matrices were used: 3-nitrobenzyl alcohol, picolinic acid and sinapinic acid. A spectrum of gramicidin-S was generated from approximately 250 attomoles of material using a molar ratio of 3-nitrobenzyl alcohol to analyte of approximately 20:1. A single peak, located at 1224 Da, was obtained from the bacterial spores. The washing liquid and extract solution from the spores were analyzed using electrospray mass spectrometry and subsequent MS/MS product ion experiments. This independent analysis suggests that the measured species represents part of the B. subtilis peptidoglycan. The on-line addition of matrix allows quasi-real-time chemical analysis of individual, aerodynamically sized particles, with an overall system residence time of less than 5 seconds. These results suggest that a MALDI-ATOFMS can provide nearly real-time identification of biological aerosols. Copyright 2000 John Wiley & Sons, Ltd.

Single Particle Mass Spectrometry–Bioaerosol Analysis by MALDI MS

“…10,11,21) Stowers et al 10) reported the on-line aerosol MALDI MS analysis of Bacillus atrophaeus spores and found a reproducible peak at a mass of 1224 Dalton, which was attributed to a part of peptidoglycan. The work done by Van Wuijckhuijse 11,21) included the on-line aerosol MALDI analysis of spores of Bacillus atrophaeus and of vegetative cells of Escherichia coli.…”

“…Software to acquire and process the data of the instrument was also developed by Weiss 7) . Stowers et al 10) and Van Wuijckhuijse 11) implemented MALDI mass spectrometry, a technique that al-…”

Improved sensitivity and mass range in time-of-flight bioaerosol mass spectrometry using an electrostatic ion guide

“…Single particle MALDI experiments provide a suitable system to access the performance of the instrument [5][6][7]. Gramicidin S particles were generated from a 50/50 H 2 O/ethanol solution of 2,5-dihydroxybenzoic acid (DHB; 3 ϫ 10 Ϫ3 M) and gramicidin S at a 100:1 matrixto-analyte molar ratio.…”

Parameters contributing to efficient ion generation in aerosol MALDI mass spectrometry

“…In 2005, Harris et al described aerosol MALDI in an ion trap mass spectrometer [36]. A number of groups have analyzed proteins, but in 2000, Stowers et al were the first to analyze Bacillus spores [37,38]. Regardless of the analyte, aerosol MALDI differs from classical bulk MALDI in a number of important ways.…”