Characterization of microorganisms by thermogravimetric analysis–mass spectrometry Original Research Article

A thermogravimetric analysis (TGA) system was interfaced to a mass spectrometry (MS) detector to investigate the thermal evolution of decomposition products from microorganisms. Traditionally, TGA–MS has been used to investigate the thermal parameters and chemical composition of materials such as the coal and lignin energy producing compounds and a wide range of technical organic polymers. The relative weight loss of biochemical species and compounds in bacteria from the TGA system allowed a comparison to the relative amounts of the same substances in bacteria from conventional microbiological extraction and isolation techniques. MS is shown to produce information rich total ion chromatogram profiles of thermal products from biochemical standards and microorganisms. The TGA thermal weight loss chromatogram (TWC) provides a degree of resolution, because the bacterial biochemical substances and components partition in a temporal fashion. Standard biochemical substances such as dipicolinic acid, polyhydroxybutyric acid, and peptidoglycan are produced in the same general temperature region in the TWC profile, and the compounds have similar mass spectra compared to those from microorganisms. Characterization of microorganisms was possible by the relation of their thermal events and extracted mass spectra to those of low and high mass model biochemical compounds.