Servopro Chroma
Thermal Conductivity

Measure inert gases in a binary mixture with Thermal Conductivity

Used in our SERVOPRO Chroma gas analyzer, the Thermal Conductivity Detector (TCD) works alongside Gas Chromatography (GC) techniques to deliver robust, accurate measurements for binary gas mixtures in industrial and medical gas applications.

The TCD consists of an electrically heated Wheatstone bridge in a temperature-controlled cell.

For GC-TCD applications, the carrier gas (helium) is passed over the reference arm of the bridge and the column effluent passes over the analyte arm under the same conditions for flow rate and temperature.

When no impurities are eluting from the column, the heat loss from the analyte arm matches that from the reference arm. When an analyte elutes from the column, it affects the thermal conductivity, changing the electrical resistance, which is measured as a signal.

Thermal Conductivity is a robust technique for determining the concentrations of gases in a binary mixture. The Thermal Conductivity detector is a universal sensor.

Analytical methods involving a TCD can be used where the constituents of the binary gas are known, such as in GC-TCD.

Related and alternative technologies

Thermal Conductivity works with Gas Chromatography to deliver measurements down to ppb levels for industrial and medical gases. TCD sensing has a relatively low sensitivity to changes in flow rates, which requires larger sample sizes. Additionally, more cost-effective solutions may be available for some applications.

Key applications

Medical gases

Air separation units

Specialty gases

Key benefits

A robust method for binary mixture analysis

Universal detector for Gas Chromatography analysis

Measures from very low concentrations up to percentage levels

Ideal for

Binary gas mixture measurements, for medical and industrial gases.

Explore the Thermal Conductivity analyzers we have for your process

Learn more about all our gas analyzer solutions that use this sensor technology.

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The Chroma is optimized to specific background gases to ensure optimum performance for your application.

  • Versatile, ultra-accurate trace gas analysis
  • Choice of non-depleting sensor technologies
  • Cost-effective solution for process control or quality monitoring
  • Works in a wide range of background gases
  • Compact 4U rack-compatible design
  • Flexible communication options

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