Thermal Conductivity

Explanation

The TCD (Thermal Conductivity Detector) Gas Chromatograph, while not as sensitive as other detectors, offers the advantage of being non-specific and non-destructive in nature. This detector comprises an electrically-heated wire or thermistor, typically made of tungsten-rhenium wire. The temperature of the sensing element is influenced by the thermal conductivity of the gas that surrounds it. Modulations in thermal conductivity occur when organic molecules displace some of the carrier gas, leading to a temperature increase in the sensing element. This change in temperature is detected as a corresponding alteration in resistance. By monitoring these resistance changes, the TCD can identify the presence of various components in the gas mixture.