Colorimetric sensor array: Do I see what you smell

This thesis describes the development of a colorimetric sensor array (CSA) and its diverse applications. Array-based vapor sensing has emerged as a powerful approach toward the detection of chemically diverse analytes. For the detection of volatile organic compounds (VOC), we have demonstrated extremely high selectivity and high sensitivity (ppb) for the detection of biologically important analytes including amines, carboxylic acids, aldehydes, and thiols. This level of sensitivity is often better than the gas chromatography-mass spectrometry (GC-MS) "gold standard". Prior electronic nose technology for the generalized detection of VOCs has generally employed arrays of sensors with extremely limited discriminatory capabilities. They are also often relatively insensitive and extremely susceptible to interference from changes in humidity.;We have developed and patented a unique chemical detection technology in which colorimetric changes in an array of dyes constitute a signal much like that generated by the mammalian olfaction system; each dye is a cross-responsive sensor. This technology uses a disposable printed array of chemically responsive dyes as the primary sensor elements. The dyes undergo reversible reactions that result in well defined color changes due to stronger chemical interactions: ligation to metal ions, Lewis or Bronsted acid-base interactions, hydrogen bonding, etc. Striking visual identification of a wide range of VOCs are easily made at part per billion (ppb) levels with extremely low error rates for Toxic Industrial Chemicals (TICs) at both their IDLH (Immediately Dangerous to Life or Health) and the much more demanding PEL (workday permissible exposure limits). Complex mixtures are easily identified, such as coffees and perfumes, making this technology ideal for quality control applications. This technology is also used for the detection and identification of pathogenic bacterium based on volatile metabolites emitted during growth.