Gas Chromatography Detectors - Ionization Detectors > The Thermal Argon Detector > Page 63


It is seen that a very inert type of sensor can be constructed having no radioactive source or other separate electron generator and yet provide a high sensitivity to all compounds that have ionization potentials of less than 11.5 electron volts. The system was found to work equally effectively using helium as the carrier and sensor gases, showing that metastable helium atoms could also be produced in the same manner.

A chromatogram demonstrating the separation of some hydrocarbons using the thermal-helium detector and the metal-free sensor displayed in figure 32, is shown in figure 33. Included in figure 33 is the same separation monitored simultaneously with an FID.

Figure 33 The Separation of a Mixture of Hydrocarbons Monitored by the Thermal Argon Detector and the FID