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What is TCD in gas chromatography?

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What is TCD in gas chromatography?

Thermal conductivity (TCD) is a commonly used detector in gas chromatography. TCD works by having two parallel tubes both containing gas and heating coils. Using this principle, a TCD senses the changes in the thermal conductivity of the column effluent and compares it to a reference flow of carrier gas.

When would you use a TCD detector?

The TCD is a universal, nondestructive, concentration-sensitive detector that responds to the difference in thermal conductivity of the carrier gas and the carrier gas containing sample. It is generally used to detect permanent gases, light hydrocarbons, and compounds that respond poorly to the FID.

What is the universal detector in GC?

In the current detector market, the mass spectrometer has been accepted as the most universal detector for gas chromatography with capabilities of both trace quantitative and definitive qualitative information.

Can TCD detect CO2?

Please note that FID will not respond to gases like CO, CO2 etc, whereas, TCD will detect them. But the problem is TCD sensitivity is much lower than FID. If CO and CO2 are present in very low concentration, then TCD will not be able to give a proper signal.

What analytes are good for TCD?

It produces a signal by measuring the thermal conductivity of the carrier gas/analyte mixture leaving the GC column. Hydrogen and helium are the two carrier gases that work best with a TCD, because they have the greatest difference in thermal conductivities from most analytes.

What types of compounds are analyzed by FID and TCD detector used in GC?

The TCD is mainly used to detect inorganic gas and components that the FID is not sensitive to. Helium is commonly used as a carrier gas. (N2 and Ar are used to analyze He and H2.) Water, formaldehyde, formic acid, etc.

Which detector for GC is the most sensitive?

flame ionization detector (FID)
The flame ionization detector (FID) is the most popular detector for gas chromatography for its reliability and its sensitivity in the detection of organic vapors.

Can TCD detect oxygen?

The TCD is also used in the analysis of permanent gases (argon, oxygen, nitrogen, carbon dioxide) because it responds to all these substances unlike the FID which cannot detect compounds which do not contain carbon-hydrogen bonds.

Which carrier gas is used with thermal conductivity detector?

Helium
Helium is typically used as the carrier gas for the TCD because of its high thermal conductivity.

What types of detectors are available for a GC?

Gas chromatography detectors

  • GC DETECTORS.
  • FLAME IONIZATION DETECTOR (FID):
  • NITROGEN PHOSPHORUS DETECTOR (NPD):
  • ELECTRON CAPTURE DETECTOR (ECD):
  • THERMAL CONDUCTIVITY DETECTOR (TCD):
  • FLAME PHOTOMETRIC DETECTOR (FPD):
  • PHOTOIONIZATION DETECTOR (PID):
  • ELECTROLYTIC CONDUCTIVITY DETECTOR (ELCD):

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