Sensitive Ionization System for the Detection of Permanent Gases and Organic Vapours by Gas Chromatography

Abstract

THE two most commonly used high-sensitivity detection devices for gas chromatography, the ‘flame ionization’¹ and the ‘argon ionization’ detectors², are insensitive to permanent gases. During an investigation into the various mechanisms responsible for ionization phenomena within the latter class of devices it was noted that under certain conditions of field and radioactive source strength, detector geometry and operating temperature, a simple ionization system using argon as carrier gas could be utilized to detect extremely low concentrations of permanent gases. The limit of sensitivity of this new mode of detector operation is up to 1,000 times greater than that reported with an earlier device³. In addition to this extraordinary response to fixed gases this same detector when operated at a different potential was found to retain certain characteristics, including the high sensitivity toward organic molecules as that noted by Lovelock² for the conventional small ‘argon detector’.