Gas Chromatography – Differential Mobility Spectrometry and Gas Chromatography – Mass Spectrometry for the detection of coliform bacteria
The use of miniaturized Gas Chromatography – Differential Mobility Spectrometry (GC-DMS) is shown for the 10 detection and identification of coliform bacteria (including Escherichia coli) grown in five different media: Colilert®-18, glucose broth, M9-medium, tryptophan broth, and tryptic soy broth. After incubation in the different media, headspace 12 containing the volatile compounds were analyzed by the GC-DMS and the results were validated by Gas Chromatography – Mass Spectrometry (GC-MS). Results showed that the GC-DMS and GC-MS were able to detect o-nitrophenol released by coliform bacteria incubated in Colilert®-18. In addition to that, GC-MS was able to detect indole compound released by coliform bacteria grown in all media. Neither GC-DMS nor GC-MS could detect 4-methylumbelliferone from the headspace of E. coli grown in media containing 4-methylumbelliferyl-β-D-glucoronide (MUG) substrate, which was available in Colilert®-18. With the miniaturized GC-DMS being portable and can be operated using ambient pressure, this method offers a potential on-site detection of coliform bacteria.