Effect of the Carrier Gas on the Sensitivity of a Thermal-conductivity Detector in Gas Chromatography

Abstract

IT is quite true that the sensitivity of the detector would be higher with a carrier gas of high thermal conductivity, provided that the hot wire can be maintained at the same temperature. In practice, however, it is not always possible to achieve this because the bridge supply voltage is generally fixed by the makers of the instrument at a level which permits safe operation with a gas of low conductivity, and to increase the bridge voltage may necessitate modification to the electrical circuit of the instrument.