Automated gas sampling system for laboratory analysis of CH4 and N2O

Analyzing the flux of CH4 and N2O from soil is labor intensive when convent ional hand injection techniques are utilized in gas chromatography. An auto mated gas sampling system was designed and assembled from a prototype devel oped at the National Soil Tilth Laboratory in Ames, IA. The sampler was eva luated for accuracy and precision when attached to a Varian(1) 3700 gas chr omatograph configured with flame ionization and electron capture detectors. The automated gas sampling system is easy to operate and provides acceptab le results (standards ranging from 1.0-5.0 ppmv CH4 and 0.342-2.0 ppmv N2O had coefficients of variation ranging from 1.7-5.6%) while providing an eco nomical approach for analyzing large numbers of gas samples with minimal la bor and equipment cost.