ABSTRACT
A dual column/dual thermal conductivity detector gas chromatograph is used to separate and determine O2, N2, CO, CO2, and CH4 in gas samples (1) . The sample is introduced as a plug into the carrier gas, and after drying in a desiccant tube it passes successively through two carefully matched gas chromatography columns. The first column contains a very polar stationary liquid phase while the second is packed with molecular sieve 13-X. Detectors are placed at each end of the column. The first column retains only CO2, which is eluted after passage of the rest of the mixture (the composite peak). The first detector thus records two peaks, one corresponding to the unresolved O2, N2, CH4, and/or CO, and the second to CO2. The gases are swept into the molecular sieve column which separates all the components. The second detector records the elution of O2, N2, CO, and/or CH4. The CO2 is irreversibly adsorbed on molecular sieve 13-X and does not elute.
