Application of gas chromatography for direct analysis of gas mixtures in the 10−4–10 Torr range

Abstract

A new technique which combines gas chromatography and UHV techniques is described for the direct analysis of the components of gaseous mixtures whose total pressure lies between 10−4 Torr and atmospheric. It therefore covers the gap of total pressure in which both mass spectrometry and traditional gas chromatography are not able to work directly and in a satisfactory way. It has been possible to detect partial pressures down to 10−5–10−6 Torr in a gas at a pressure of 1 Torr. Concentrations down to 1–10 ppm are, therefore, measured. Due to the limited quantity of the gas required for the analysis, this technique is particularly suitable for the quantitative measurement of impurities present in the filling gas of various devices, even during their operation. Results obtained in a practical case using the technique are reported.