Gas Chromatographic Analysis of the Soil Atmosphere: Automatic Analysis of Gas Samples For O2, N2, Ar, CO2, N2O and C1-C4 Hydrocarbons

Abstract

A method is described for the quantitative analysis of gaseous mixtures of N₂, O₂, Ar, CO₂, N₂O and C₁–C₄ hydrocarbons. Batches of up to 40 samples in syringes are injected by an automatic system. Each sample is split between three parallel columns, two of which are connected to thermal conductivity detectors for the determination of the inorganic gases, and the other to a flame ionization detector, for the determination of hydrocarbons. The latter is one of two identical columns, each of which can be used in turn while the other is automatically backflushed to remove compounds with long retention times. Chromatograms showing the mixtures of hydrocarbons found in soil are included, to illustrate the variations in relative and absolute concentrations of each gas which can occur under natural conditions.