Automated gas injector system for gas chromatography: Atmospheric nitrous oxide analysis

Improving estimates of the contribution of the terrestrial ecosystems to the global N2O budget will require high-frequency and large-scale gas flux measurement programs. Such programs are typically best performed by automated sampling systems. We developed a new automated gas injector system for gas chromatography. The system is based on a commercially available liquid sample changer and subambient pressure gas handling. The injector fills a sample loop and measures the exact sample pressure. The autosampler allows the unattended analysis of up to 220 N2O gas samples contained within 10-mL Vacutainers and an unlimited number of reference samples. A software package was developed to run the analytical system, including a gas chromatograph equipped with an electron capture detector for N2O analysis. Final results are calculated using the sample pressure and the integrated area data.