(545e) A Colorimetric Sensor Array for the Detection of Toxic Industry Chemical (Tics)

Array-based vapor sensing derives from the biomimetic concept of using many cross-responsive sensor elements, rather than specific lock-and-key receptors. As with the mammalian olfactory system, it is the composite response of the array that that identifies an odorant or mixture of odorants.  Electronic nose technologies of this type generally use sensors based on weak chemical interactions (e.g., physisorption, absorption, etc.), and they suffer from some severe limitations:  the detection of compounds at low concentrations relative to their vapor pressures is difficult; the discrimination between compounds within a similar chemical class has been limited; and perhaps most importantly, interference from the large environmental changes in humidity remains problematic.  In recent years, we have developed a rather different, but quite simple, approach to an "optoelectronic nose" based on a colorimetric array initially using metalloporphyrins and more generally chemically-responsive dyes. The design of a colorimetric sensor array (CSA) is based on stronger dye-analyte interactions than those that cause simple physical adsorption, which results in great improvement in discriminatory power. We report here the use of a colorimetric sensor array for the identification and semi-quantitative analysis of a wide range of toxic industrial chemicals (TICs). Excellent detection limits (generally below the permissible exposure limits (PEL)) are demonstrated, as well as clear differentiation among 10 TICs, 9 common chemical interferents, and binary mixtures thereof.