Gas Chromatography–Differential Mobility Spectrometry and Gas Chromatography–Mass Spectrometry for the detection of coliform bacteria

Abstract

The use of miniaturized Gas Chromatography–Differential Mobility Spectrometry (GC–DMS) is shown for the 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 containing the volatile compounds was 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.