Abstract
We propose a portable gas analyzer (PGA)-based system for analyzing stored methane (CH4) and carbon dioxide (CO2) samples more rapidly compared to gas chromatography (GC) for application in the closed chamber technique. A gas analysis system was established using an ABB LGR-ICOS gas analyzer, which was connected to a carrier gas flow line with nitrogen as the carrier gas and to a gas injector equipped with a septum. This new system enabled more rapid analysis of CH4 and CO2, within 2 minutes, which was more than three times faster than GC. The linearity of gas measurements using the PGA-based system was evaluated by measuring the peak heights of known concentrations of CH4 and CO2 gases introduced into the system. The results demonstrated excellent linearity, with R² values exceeding 0.998. The repeatability of the gas measurements was high, as indicated by the low coefficient of variation (CV), with all CVs remaining below 3%. To validate the PGA-based system, we compared its results with those obtained from GC. The results from the system showed a high correspondence with the GC measurements, with R² values exceeding 0.995 and the ratio of CH4 and CO2 concentrations measured by the PGA-based system relative to those measured by GC being nearly 100%. Overall, we concluded that the PGA-based system is a robust method for measuring CH4 and CO2 concentrations of stored samples in sealed containers more rapidly compared to GC.
