title: Si:WO(3) Sensors for highly selective detection of acetone for easy diagnosis of diabetes by breath analysis.
abstract: Acetone in the human breath is an important marker for noninvasive diagnosis of diabetes. Here, novel chemo-resistive detectors have been developed that allow rapid measurement of ultralow acetone concentrations (down to 20 ppb) with high signal-to-noise ratio in ideal (dry air) and realistic (up to 90% RH) conditions. The detector films consist of (highly sensitive) pure and Si-doped WO(3) nanoparticles (10-13 nm in diameter) made in the gas phase and directly deposited onto interdigitated electrodes. Their sensing properties (selectivity, limit of detection, response, and recovery times) have been investigated as a function of operating temperature (325-500 degrees C), relative humidity (RH), and interfering analyte (ethanol or water vapor) concentration. It was found that Si-doping increases and stabilizes the acetone-selective epsilon-WO(3) phase while increasing its thermal stability and, thus, results in superior sensing performance with an optimum at about 10 mol % Si content. Furthermore, increasing the operation temperature decreased the detector response to water vapor, and above 400 degrees C, it was (<or=0.7) always below the threshold (10.6) for fake diabetes detection in ideal conditions. At this temperature and at 90% RH, healthy humans (<or=900 ppb acetone) and diabetes patients (>or=1800 ppb) can be clearly distinguished by a remarkable gap (40%) in sensor response. As a result, these solid state detectors may offer a portable and cost-effective alternative to more bulky systems for noninvasive diabetes detection by human breath analysis.
authors.affiliation: Particle Technology Laboratory, Department of Mechanical and Process Engineering, Institute of Process Engineering, ETH Zurich, CH-8092 Zurich, Switzerland.
authors.forename: Marco
authors.initials: M
authors.lastname: Righettoni
authors.forename: Antonio
authors.initials: A
authors.lastname: Tricoli
authors.forename: Sotiris E
authors.initials: SE
authors.lastname: Pratsinis
mesh_terms: D000096:Acetone / Q000032:analysis* / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D001944:Breath Tests / Q000295:instrumentation* / Q000379:methods*; D003920:Diabetes Mellitus / Q000175:diagnosis*; D006046:Gold / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D012825:Silicon / Q000737:chemistry*; D013499:Surface Properties; D014414:Tungsten / Q000737:chemistry*
chemical_list: D000096:Acetone; D006046:Gold; D000537:Aluminum Oxide; D014414:Tungsten; D012825:Silicon