Automated Gas Chromatographic System for Rapid Analysis of the Atmospheric Trace Gases Methane, Carbon Dioxide, and Nitrous Oxide

Abstract

To study the fluxes of the radiative active trace gases CH4, CO2, and N2O, a gas sampling and analytical device was developed. It is a useful tool for accurate gas sampling in the field and enables the subsequent fully automated analysis of the gas samples in the laboratory. The computer‐controlled analytical system consists of a gas chromatograph equipped with a flame ionization detector (FID), an electron capture detector (ECD), and a pressure‐controlled autosampler for 64 sample containers. The system automates sample injection, the analysis of CH4, CO2, and N2O in each sample and the subsequent evacuation of the sample containers. It is equipped with a second alternative sample inlet for manual syringe injection. This inlet is suitable for analyzing small volumes of gas samples (3 mL). The gas sampling system for use in the field consists of evacuated sample bottles (100 mL) with Teflon cocks combined with a small battery‐driven field sampler with a pressure sensor. This device enables an on‐site control of the vacuum integrity of the sample bottles during sampling and purging of the dead volumes between the sampler induction pipe and the sample container.

Evidence for methane production by saprotrophic fungi

“…Millipore, Schwallbach, mesh 80/100) was 3.2 m and 1/8 inch in diameter. The length of the precolumn was 0.8 m. The GC gas flow scheme and automated sampling was that of Mosier and Mack 37 and Loftfield et al 38 , and peak area integration was undertaken with the Software PeakSimple, version 2.66. The s.d.…”

Organic sediment formed during inundation of a degraded fen grassland emits large fluxes of CH<sub>4</sub> and CO<sub>2</sub>

“…For this purpose, the incubation vessels were closed for one hour by gas-tight lids equipped with plugs for gas sampling. Gas samples were taken from the headspace using evacuated glass flasks (100 mL) at 0, 0.5 and 1 h and were analyzed by the gas chromatograph (GC 145, Shimadzu) (Loftfield et al, 1997). We assumed linearity.…”

“…Silicone probe samples were diluted with N 2 to concentrations which were in the measurement range of the GC, filled into evacuated 100 ml glass flasks and analyzed with the gas chromatograph (Shimadzu GC-14B, ECD for CO 2 , FID for CH 4 ) (Loftfield et al, 1997). After sampling, the water and air in the silicone probes were removed and the probes flushed with N 2 to ensure anaerobic conditions.…”

Atmospheric methane uptake by tropical montane forest soils and the contribution of organic layers

“…Pressure was checked with a manometer during sampling to assure that containers had been evacuated properly and were filled to atmospheric pressure. Gas samples were analyzed within 48 h following sampling using a gas chromatograph (Shimadzu GC-14B, Duisburg, Germany) equipped with a flame ionization detector (FID) and an electron capture detector (ECD) combined with an autosampler (Loftfield et al 1997). Gas concentrations were calculated by comparing integrated peak areas of samples with four standard gases (1.5, 2.0, 10 and 20 ll l -1 standard concentrations of CH 4 ; and 350, 700, 1500, 5000 ll l -1 standard concentrations of CO 2 ; Deuste Steiniger GmbH, Mühlhausen, Germany).…”