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 m-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.