Detector Systems
Thermal conductivity detector (TCD)
Because of its exceptionally high thermal conductivity and chemical inertness, He is the recommended carrier gas: it gives large thermal conductivity differences with all compounds except H (considerations necessary in H analyses are discussed later). With He as carrier, the TCD exhibits universal response. For propane, the sensitivity limit is about 400 picograms/ml of He carrier gas.
The TCD exists in two configurations: either its exhaust vent tube exits at the top of the detector or the exhaust vent tube returns to the inside of the oven for connection to an FID or other device.
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Final Pressure Regulators |
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and Gauges |
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| Makeup Gas | Inlet |
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| MAKEUP GAS |
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| Makeup Gas Adapter: | ||||||||||
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| Capillary Columns Only | |||||
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| Flow Diagram, Thermal Conductivity Detector (TCD) |
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