Other

John L Middleton

Edwin L Karas

Raymond Annino

Richard Villalobos

Dale E Lueck

Michael L Bartlett

A dual-column, dual-detector gas detector and analyzer employs both a photo-ionization detector and a flame-ionization detector. In a survey mode, samples of ambient air are driven through both detectors, and the outputs of both detectors are used to determine the presence of one or more gasses. In analysis mode, fixed-volume samples of ambient air are driven through two elution columns having different properties. The output of each elution column is fed to one of the detectors. The arrival times of gas peaks at the two detectors are employed to develop two lists of candidate gasses. The lists are cross-checked for the presence of each candidate on both lists. Candidates identified from their presence on both lists are identified. A further check attempts to identify candidates which are identifiable from their presence on one of the lists, and not on the other. Components identified in this way are added to the final list. Unidentified components are discarded, although their presence is noted and reported as unknown. Portability is retained by eliminating isothermal ovens and by reducing the quantity of hydrogen required. A simplified way of characterizing temperature corrections of elution columns is disclosed.

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Lexington, MA, United States of America

John L Middleton