Gas chromatography utilizing SAW sensors

The performance of a high-speed (10-15-s) gas chromatography system for the detection of illicit materials is described. The system is based on an isothermal capillary column gas chromatograph (GC) and a 500-MHz surface acoustic wave (SAW) crystal decoder. The SAW sensor operates as an integrating GC detector and is able to continue operating for extended periods without replacement by using periodic in situ cleaning. Specificity to materials of interest is enhanced by controlling the sorption/desorption characteristics of the SAW crystal surface. The system is capable of operating over a wide range of vapor concentrations extending from femtograms to many nanograms without overloading.<
>