Imaging of Single Particles as a Method to Understand Mass Spectral Variations in Bio-Aerosol Mass Spectrometry (BAMS)

摘要

A field deployable, Bio-Aerosol Mass Spectrometry (BAMS) instrument is being developed at Lawrence Livermore National Laboratory for the real-time single cell detection and identification of Bacillus Anthracis and other biological aerosols. BAMS has shown the ability to distinguish single Bacillus spores from vegetatitive cells using low mass ions but, greater spectral quality at higher masses is necessary for species level differentiation. Automated particle identification relies upon relative peak area as well as accurate peak mass assignment. High mass taxonomical biomarkers such as small acid soluble proteins, SASP's, (6-10kDa) are species specific but their potential value is currently reduced in BAMS due to shot to shot variations in ion peak locations at higher masses. The source of some mass spectral variations is due to the size of the particle and the position at which the particle interacts with the desorption/ionization (DI) laser beam and is therefore worthy of investigation. A novel technique utilizing on-the-fly imaging is being developed to assist in this endeavor.