Electronic nose technology for the detection of microbial and chemical contamination of potable water

Comparisons were made between two electronic nose systems employing conducting polymer sensor arrays for the early detection and discrimination between bacterial species (Escherichia coli, Enterobacter aerogenes and Pseudomonas aeruginosa, 102 CFU mL−1), fungal spores (Aspergilus fumigatus, Fusarium culmorum and Penicillium sp., 102 spores mL−1) and trace amounts (ppb) of pesticides (DDT and dieldrin). Using PCA, DFA and cluster analysis, it was possible to differentiate between the different bacterial and fungal species after 24 h incubation at 25 °C. However, 10 and 100 ppb of the pesticides could not be effectively discriminated from the controls. For bacterial contaminants good correlation between the two different electronic nose systems was possible. Head-space solid phase microextraction (HS-SPME) technique with a gas chromatograph, was used to evaluate and analyse volatile profiles of bacterial cells inoculated in the presence of trace amounts of heavy metals. The resulting chromatograms demonstrated that the volatile patterns from bacterial samples were different from those where a low amount of heavy metals were added.