Abstract: A method and apparatus for identifying and analyzing vapor elements, using a preconcentrator collector. The preconcentrator collector collects and preconcentrates chemical vapors to be detected and identified before chromatographic analysis using surface acoustic wave gas chromatograph (SAW/GC) technology. The preconcentrator collector is used in conjunction with a sensor in an SAW/GC detector in the apparatus. A physical parameter associated with the sensor changes in a defined manner upon exposure of the sensor to an unknown vapor, permitting identification of the individual vapor elements. The preconcentrator collector of the invention includes a body portion having an inlet and an outlet, and a stack of collector plates disposed in the body portion. The collector plates are made of a material that is easily micromachinable and easily cleanable, such as silicon, silica or fused quartz.

Abstract: A detector and method for identifying a chemical vapor and determining its concentration in the ambient atmosphere. The chemical detector apparatus preferably includes a means of collecting vapors in one atmosphere and transferring the vapors by injection into a chromatographic separation column. The exit of the separation column is confined by a nozzle which causes the vapors to be focused into a specific area of an acoustic wave interferometer wherein standing waves are created by constructive interference of waves reflected from a plurality of reflecting elements. Identification of vapor species is by a combination of timed adsorption rate peaks and temperature programmed desorption rates of the individual vapor species.