Detection of the picolinic acid biomarker inBacillus spores using a potentially field-portable pyrolysis?gas chromatography?ion mobility spectrometry system

Abstract

The absence of a field-portable device to provide real-time detection of Gram-positive bacterial spores has prompted the interfacing of a pyrolysis (Py) module to an existing, hand-held gas-chromatography—ion-mobility spectrometry (GC/IMS) device. In this configuration, spore detection is achieved by the observation of picolinic (2-pyridinecarboxylic) acid (PA), which is the most characteristic pyrolysis decomposition product of the parent dipicolinic (2,6-pyridinedicarboxylic) acid (DPA). Positive identification of PA was demonstrated using a laboratory-based GC instrument with dual, parallel mass spectrometry (MS) and IMS detectors. Spores and vegetative microorganisms of the genus Bacillus were characterized by the presence and absence of DPA, respectively, and the picolinic acid marker was identified from the GC/IMS and GC/MS profiles. A field-portable prototype Py-GC/IMS system is described and appears to provide similar bioanalytical information with respect to the laboratory-based system. Preliminary results of this study indicate that the degree of compound separation afforded by a short GC capillary column guards against common environmental interferences including urban particulate matter and biological particles such as fungal spores and pollen. © 1996 John Wiley & Sons, Inc.