Enhanced detection of m-xylene using a preconcentrator with a chemiresistor sensor

Chemiresistor chemical microsensors are being investigated as a tool for environmental monitoring. These devices can provide real-time in situ chemical concentration data for solvent-contaminated sites of interest. Detection limits of an unaided chemiresistor, however, are typically in the range of 1/1000th of the saturated vapor pressure of a given analyte, which may not be sufficient for chemicals with high vapor pressures and low desired detection limits. Tests were conducted in this study to determine the response of a chemiresistor sensor to in-xylene with and without preconcentration. Results showed that by adding a microfabricated preconcentrator to a chemiresistor sensor, detection limits of m-xylene were decreased by more than two orders of magnitude, from 13.5 ppm to 61.8 ppb, without significantly increasing the complexity of the sensing system. (C) 2004 Elsevier B.V. All rights reserved.