Patent ID: 6212938
Filing Date: 2001-04-10
Classification: G01N

Abstract:
In the art of gas chromatography, a method of detecting a vapor that contains a plurality of chemical analytes, and providing a visual representation of its odor characteristics that can be uniquely and readily identified by humans, comprising the steps of:a. supplying a carrier gas having a collection of the vapor desorbed therein to a gas chromatographic column so as to separate the vapor's chemical analytes in time;b. during a predetermined analysis period, applying the effluent vapor from the chromatographic column to a SAW device that includes a vibratory crystal having a base frequency, such that different analytes exit the chromatography column at different times to physically interact with the surface of the crystal;c. also during the analysis period, repetitively interrogating the SAW device to measure the vibration frequency of the crystal;d. applying signals representing the deviations of the measured crystal frequencies from the base frequency to a display device to produce a polar representation in which a complete rotation corresponds to the difference in time between the beginning and ending of the analysis period, such that the data points on the display device are separated by angles proportional to the time differences between data points; ande. adding lines on the display interconnecting adjacent data points, thereby producing a unique closed-image visual pattern which is distinctly indicative of the odor of the vapor.