ARS | Publication request: Automated gas sampling system for laboratory analysis of CH4 and N2O

Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 8, 2000
Publication Date: March 3, 2001
Citation: Arnold, S.L., Parkin, T.B., Doran, J.W., Mosier, A.R. 2001. Automated gas sampling system for laboratory analysis of CH4 and N2O. Communications in Soil Science and Plant Analysis 32:2795-2807.

Interpretive Summary: Analyzing soil atmosphere is labor intensive when conventional hand injection techniques are utilized in gas chromatography to determine the soil’s ability to emit and sorb greenhouse gases such as nitrous oxide, and methane. An automated sampling device was designed and assembled, then evaluated for its usability along with its accuracy and precision of resulted obtained, when attached to a gas analyzing device. The automated sampler proved to be easy to operate with minimal labor requirements along with acceptable results. The large number of samples that can be automatically analyzed (things that go bump in the night) makes the sampler an economical approach for completing large samplings with minimal labor.

Technical Abstract: Analyzing the flux of CH4 and N2O from soil is labor intensive when conventional hand injection techniques are utilized in gas chromatography. An automated gas sampling system was designed and assembled from a prototype developed at the National Soil Tilth Laboratory in Ames, Iowa. The sampler was evaluated for accuracy and precision when attached to a Varian1 3700 gas chromatograph configured with flame ionization and electron capture detectors. The automated gas sampling system is easy to operate and provides acceptable 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 economical approach for analyzing large numbers of gas samples with minimal labor and equipment cost.