Thermo Scientific FOCUS GC, Instruction Manual

Page: 178 / 356

Chapter 9
Thermal Conductivity Detector (TCD)
Selecting TCD Operating Parameters
178 Instruction Manual
When using low thermal conductivity gases, the temperatures reached by the
filaments are very high. Table 9-2 contains the experimental filament temperature
values corresponding to the applied voltages when using argon.
For samples with a wide range of concentration percentage (1–100%), use the
following values:
• detector temperature: 10 °C higher than the maximum temperature reached by
the column oven during the analysis, but not higher than 300 ºC
• filament voltage: 5 V
Suggested Operating Values
Table 9-3 contains the suggested operating values for the detector as a function of
the concentration range and detector temperature.
Table 9-2. Filament Temperature Values for Argon
Detector Temperature 100 ºC Values
Voltage (V) 5 6 7 8 9 10
Filament Temperature (ºC) 235 275 315 355 395 435
Table 9-3. Selectable TCD Parameters
Concentration
Range
Detector
Temperature
Filament
Temperature
Filament
Voltage
Mode
ppm—5%
0.5–100%
100 ºC
100 ºC
180 ºC
—
—
5 V
CT
CV
ppm—5%
0.5–100%
180 ºC
180 ºC
270 ºC
—
—
6 V
CT
CV
ppm—5%
0.5–100%
240 ºC
240 ºC
330 ºC
—
—
6 V
CT
CV