Bake Out the Agilent Micro Electron Capture Detector

Answer

This Information Applies To: Micro Electron Capture Detector (uECD)

Issue

Baking the micro electron capture detector (µECD) at high temperatures can remove sample contaminants that have deposited on the detector surfaces. 

Warning: The µECD uses hazardous β- and X-radiation, which is encased in a safe housing. Exposure to radiation can cause injury and harm. Operators may perform an µECD bake out. Personnel trained and licensed appropriately to handle radioactive materials must perform all other maintenance procedures.

Items required 

• Ferrule, no hole 10/pk (p/n 5190-4054) 
• Column nut, any of the following:
  • Column nut, universal (p/n 5181-8830)
  • Blanking plug, finger-tight style (p/n 5020-8294)
  • Finger-tight column nut (p/n 5020-8292)
  • Column nut, collared, self-tightening, inlet/detector (p/n G3440-81011)

Steps to follow

1. Load the normal GC method and wait for the GC to become ready. 

2. Note the value of the µECD signal output for comparison with value after the bake-out. 
   

   • 7890 GC Systems: On the instrument front control panel, press [Front Det] or [Back Det] then scroll to output.
   • 7820A GC Systems: On the Agilent software keypad (remote controller), click [Front Det] or [Back Det] then scroll to output.
   • 8890 GC Systems: On the touch screen or the browser interface, go to Home > Status listing > +Add. Select the detector’s output from the drop-down list, then select Add.
   • 8860 GC Systems: On the browser interface, go to Home > Status listing > +Add. Select the detector’s output from the drop-down list, then select Add.

3. If the column maximum temperature is < 250 °C, remove the column from the detector, otherwise, jump to step 4:

   1. To cool the oven and detector, load the GC maintenance method 
   2. Remove the column from the detector
   3. Plug the detector connection with the column nut and the no-hole ferrule. 
   4. Turn off the carrier gas and remove the column from the GC inlet.
      

      Warning: If using hydrogen as a carrier gas, turn off the hydrogen supply and remove the column to prevent an oven explosion.

       

4. Set normal detector operating flows. If the column has not been removed from GC inlet, maintain inert carrier gas flow through the column.

5. Set the temperature zones to the bake out temperatures:

   Caution: Do not exceed the column manufacturer's recommended temperature, as it will damage the column. If the bake out temperature exceeds the recommended temperature, remove the column and turn off the inlet gas flows.

   1. Set the detector temperature to 350 to 375 °C and the make up gas flow to 60 mL/min.

   2. If the column is installed in the µECD, set the oven temperature to 250 °C. If the column is uninstalled, leave the oven off.
      To bake out the GC inlet see How to Bake-out the Split/Splitless Inlet (S/SL) on Agilent GC Systems.

6. Hold at bake out temperature for several hours or until the baseline settles at a lower value. The baseline will typically rise, then fall to a final value lower than the initial baseline (Figure 1): 

   
   Figure1. Typical bake out signal profile
   

7. Allow the instrument to cool and reinstall the column if appropriate.

8. Load the normal analytical method and allow the system to equilibrate.

9. Check the µECD output value. It should be lower than the first reading. If it is not, contact your local Agilent support

Learn how to effectively operate your Agilent GC Detectors:  GC-0GEN-1013s - GC Detectors Theory and Operation e-learning course available from Agilent education.