Vapor detection with high speed gas chromatography

• Main Authors: ACHTER; EUGENE K, ROUNBEHLER; DAVID P, GERNES; DAVID B, LIEB; DAVID P, TAFRESHI; ABDUL
• Format: Patent
• Language: English
• Published: 28.04.1992
• Subjects: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; PHYSICS; TESTING

Disclosed are a method and apparatus for high speed, selective detection of vapors of specific compounds, particularly nitrogen-containing compounds, utilizing, a bypass branch and high speed gas chromatography for improved selectively and sensitivity of detection. A system with two gas chromatographs (GC's) alternating in series with two pyrolyzers provides two time intervals of detection in a downstream detector, with the second time interval containing signals delayed and further separated relative to signals from the first time interval. The bypass branch, in diverting a portion of the flow of gas samples from passage through the second gas chromatograph and second pyrolyzer, avoids interferences in the first time interval of detection from non-GC-retained compounds decomposed in the second pyrolyzer. Also disclosed is an arrangement for rapid, precise heating of vapor concentrator tubes in which vapors are rapidly focussed and then injected into a GC, and for rapid, precise heating of the GC's.