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Long term monitoring of methane in the atmosphere by multiplex gas chromatographyMethane is of interest in the study of the Earth's atmosphere because of its implication in the future global warming of the surface. This warming is produced by the absorption of infrared energy by trace gases. It has been estimated that in the next 40 to 50 years, methane could contribute 20 to 25 pct. as much atmospheric warming as that expected from carbon dioxide increases. Studies to examine sources, sinks, and cycles of methane will require analytical methods capable of continuous unattended measurement with temporal resolution of an hour or less for weeks at a time. Gas chromatography (GC) is one of the most practical methods available to conduct the analysis of air, but limitations in this technique still exist which can be alleviated with multiplex GC (MGC). MGC is a technique where many samples are pseudo-randomly introduced to the chromatograph without regard to the length of time required for an analysis. The resulting data must then be reduced using computational methods such as cross correlation. In the technique reported, a tube packed with silver oxide was used at the inlet of the GC column to create concentration pulses of methane in a sample stream of air. By using only one carrier, i.e., ambient air, an effective and accurate method to monitor the variations in concentration of methane in the atmosphere over long periods of time was developed. Methane in ambient air was monitored for an eight day period and an interesting temporal variability was found. This work has shown the utility of a relatively simple MGC for the analysis of a real environmental sample.
Document ID
19930073173
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Valentin, Jose R.
(NASA Ames Research Center Moffett Field, CA, United States)
Carle, Glenn C.
(NASA Ames Research Center Moffett Field, CA, United States)
Phillips, John B.
(University of Southern Illinois Carbondale., United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1985
Publication Information
Publication: First Symposium on Biospheric Research
Subject Category
Environment Pollution
Accession Number
93N70620
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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