Pyrolysis-Gas Chromatography/Ion Mobility Spectrometry Detection of the Dipicolinic Acid Biomarker in Bacillus subtilis Spores during Field Bioaerosol Releases

摘要

An automated pyrolysis-gas chromatography/ion mobility spectrometry (Py-CG/IMS) instrument was developed for bioaerosol detection and remotely tested under field conditions. The prototype system combines a commercially available, hand-held GC/IMS device with a specially built particle collector /pyrolyzer front-end, consisting principally of a platinum heater, a 1" dia. quartz micro-fiber filter and a 60 L/mina ir pump that can be operated in a stand-alone mode or in series with a particle concentrator. During repetitive tests (60/hour), submicrogram quantitites of Bacillus endospores were detected by sensing picolinic acid and pyridine that act as biochemical marker compounds for the characteristic dipicolinic acid moieties in bacterial spore cell walls. Characterization of the products form the pyrolyzed bioaerosol was achieved independently with a laboratory bench system using a parallel Py-GC/MS/IMS configuration where a common Py-GC flow is split to the IMS and to a mass spectrometer (MS) in parallel with the IMS system. In this way, corresponding signal peaks can be identified using the NIST mass spectral libraries. In addition to its potential use as a "trigger" (preliminary warning device) for the presence of specific classes of biological compounds, the system retains its capability to detect and identify a broad range of volatile and semivolatile organic compounds.