Discrimination of Chemical Profiles of Some Bacterial Species by Analyzing Culture Headspace Air Samples Using TD-GC/MS
Charles Lawrence Paul Thomas.
In an attempt to discriminate and identify several bacterial species, headspace air samples above a series of bacterial
cultures were interrogated using a TD-GC/MS system. Three microorganism strains with relatively low pathogenic
character – Escherichia coli, Bacillus subtilis and Staphylococcus aureus – were investigated during a period of 72 hours
from the inoculation. Air samples with a volume of 1 L each were collected from the headspace above the bacterial cultures
in agar growth medium of a 5 cm3 volume kept in 30 cm3 glass vials, in Tenax-Carbograph desorption tubes, by using
a custom-built sampling unit based upon a portable air sampling pump. One sample was taken for each of the 10 different
cultures of a bacterial strain, at 24, 48 and 72 hours from the incubation. The adsorption tubes were analyzed using
the TD-GC/MS system and the resulting datasets – chromatograms and associated mass spectra – were used to produce a
qualitative insight into the chemical profile of the headspace air above the bacterial cultures. Analysis by TD-GC/MS indicated
that the chemical profile of the headspace air samples was complex and changed during the three days monitoring
period; also, there appeared to be a series of chemicals specific to individual species of microorganisms.
Keywords: Microorganisms identification, bacterial chemical profile, TD-GC/MS.
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