Agilent Technologies 6890 Series, Руководство по обслуживанию, Страница: 336 / 867

25 of 26
Jun 2001
Detectors
Agilent 6890 Gas Chromatograph Service Manual
Micro-cell Electron Capture Detector (
µ
-ECD) 341
Maintaining a
µ
-ECD detector
Maintaining a
µ
-ECD detector
µ
-ECD bakeout (thermal cleaning)
If your
µ
-ECD baseline is noisy or the display frequency is too high (i.e.,
≥
1000), you should perform a thermal cleaning (also called a “bakeout”) of
the detector. Before performing a bakeout, verify that the carrier supply gas
and flow system are leak- and contaminant-free.
Caution Detector disassembly and/or cleaning procedures other than thermal should
be performed only by personnel trained and licensed appropriately to handle
radioactive materials. Trace amounts of radioactive
63
Ni may be removed
during these other procedures, causing possible hazardous exposure to
β
- and
x-radiation (bremsstrahlung).
WARNING To prevent possible hazardous contamination of the area with radioactive
material, the detector exhaust vent must always be connected to a fume hood,
or otherwise vented in compliance with the latest revision of Title 10, CFR,
Part 20, or with state regulations with which the Nuclear Regulatory
Commission has entered into an agreement (USA only). For other countries,
consult with the appropriate agency for equivalent requirements.
1. Record the
µ
-ECD “Output” value from GC display. If the number is equal
to or greater than 1000, you should continue with this procedure.
2. Remove the column from the detector.
3. Cap the bottom of the makeup gas adapter with a blank column ferrule
and column nut.
4. Set the makeup gas flow rate to 60 mL/min. Set the detector temperature
between 350 and 375°C.
5. Set the oven temperature to 250°C.
6. Allow thermal cleaning to continue for several hours, and then cool the
system to normal operating temperatures.