3-sensor array for hand held breath diagnostic tool

ABSTRACTPolymorphic transitions in nanocrystalline metal oxides leads to structural transformations resulting in differing properties at varying operating temperatures. Nanocrystalline MoO3 transforms from a metastable monoclinic phase to stable orthorhombic phase when heat treated in the temperature range of 420C to 500C. Gas sensing results have shown that at 420C MoO3 is sensitive to Isoprene, a 450C it shows sensitivity to CO2 and to ammonia at 500C. DSC data has proved that MoO3 changes crystal structure to monoclinic at 420C and to orthorhombic at about485C. This confirms a correlation between structure and gas sensing properties of MoO3. Using this knowledge a hand-held diagnostic tool is developed to monitor specific breath gases which can be biomarkers for diseases. The device consists of three sensors, the read-out gives a real time resistance value for each resistive sensor which is stored in a microprocessor. This is a one of a kind handheld tool for disease detection using ceramic sensors as detectors for gases which are known to be biomarkers for diseases.