The problem of rapid detection of bacteria for 'in-field' applications is addressed by way of a portable 'electronic nose' comprised of five metal oxide semiconductor (MOS) gas sensors in an array for the discrimination of volatile organic compounds (VOCs) associated with bacteria species such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). A prototype portable sensor array unit (PSA unit) is presented capable of heating and taking measurements from five MOS gas sensors using a 7-volt power source. An array of five sensors based on zinc oxide (ZnO) is produced suitable for the operational requirements for portable applications. This was achieved be means of zeolite modification where a selection of these microporous aluminosilicalite structures (H-ZSM-5, H-ZSM-22 and H-Y) were incorporated into the ZnO sensor as admixtures, overlayers, admixtures as an overlayer and admixtures with overlayers using commercial screen-printing methods. Unique signal patterns towards ethanol and acetone, two key markers identified for the model bacteria selected for this thesis, were achieved at low ppm concentrations (a detection limit of 2 ppm is reported) using just one MOS material with various zeolite modification strategies.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:644422 |
| Date | January 2015 |
| Creators | Newton, E. J. |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1461145/ |
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