Pyrolysis Mass Spectrometry (PyMS) with computerized pattern
recognition can be used for the rapid chemotaxonomy of bacteria.
Differences in characteristic ion intensity ratios typically
distinguish the PyMS spectra of bacterial species. Any taxonomic
method based on pattern recognition from PyMS spectra must produce
reproducible, distinct patterns. We examined three factors which
might affect PyMS spectral reproducibility. First was lack of
synchronization between pyrolysis initiation and the MS scan.
Because mass transfer rate for pyrolysate varies rapidly after
pyrolysis initiation, we hypothesized that synchronization
inconsistency could affect the ratios. This hypothesis proved
correct.
Even normalized PyMS bacterial spectra vary as a function of
total ion intensity. This might be caused either by irregular,
"lumpy" application of the microbial sample to the pyrolysis wire or
by total mass variations. For representative bacteria we
demonstrated much greater spectral consistency by using
electrodeposition to coat the wires smoothly. This work reports
significant advances in PyMS for rapid microbial taxonomy potentially
applicable to a compliance context.