RAPID ANALYSIS OF CLIMATE GASES BY WIDE BORE CAPILLARY GAS-CHROMATOGRAPHY

A gas chromatographic method that gives sensitive and rapid (3.3 min) measurement of the three greenhouse gases CO2, CH4, N2O is described. A wide bore capillary column operated at optimal conditions gave sufficient separation to allow a switch of the column flow between two detector systems (TCD and FID in series, and ECD) during the chromatogram; thus, all three gases could be analyzed with a single sample injection. Application of a peristaltic pump allowed gas samples to be transfered directly from gas sampling vials, through a drying agent [Mg (C10(4))2] and into the injection loop (0.5 mL). Back flushing of the injection system (pump and drying agent) with He between each injection ensured minimal carry over between samples (< 0.6%). Experiences with storage of gas samples in vials with butyl rubber septa are described.