Increasing response of semiconductor gas sensor by using preconcentration method

Preconcentration method is usually used in gas chromatographic analysis system for gas condensation in detection of wound pathogen and measurement of low concentrations of odorous components. Preconcentrators (traps) consist of a stainless-steel or glass tube packed with granular adsorbent material. Desorption occurs when a current is passed through the stainless steel tube or through a metal wire coiled around the glass tube. Recent years, there are some reports about the applications of preconcentration method in sensor systems, such as surface acoustic wave (SAW) sensor micro array for indoor air quality monitoring, and silicon microchannels with the carbon nano-powder for micro-fluidic reactor for benzene detecting. In this report, preconcentration method is used in a gas sensor system. The response of semiconductor gas sensor to indoor formaldehyde (HCHO) vapor was increased by using this method.