Bake Out the Agilent Flame Ionization Detector

Answer

This Information Applies To: Agilent GC Systems with flame ionization detector (FID)

Issue

Baking out the flame ionization detector at high temperatures can remove sample contaminants that have deposited on the detector surfaces. 

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)
• FID/NPD capillary adapter (Adaptable FID style only) (p/n 19244-80610) 

Steps to follow

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

2. Note the value of the FID 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. Determine if you need to remove the column. The detector bake-out temperature is 350 to 375 °C. If this bake out temperature exceeds the column manufacturer's upper temperature limit, remove the column otherwise, jump directly 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. For adaptable FID style configurations, make sure that the capillary adapter is installed.
   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. Load the normal operating flows. If the column has not been removed from GC inlet, maintain inert carrier gas flow through the column.

5. Light the FID flame.

6. 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, or 25 °C higher than the normal operating temperature.

   2. Set the oven temperature to 250 or 25 °C above the normal maximum operating temperature. Do not exceed the inlet temperature.

   3. If the column is still installed, set the inlet temperature to 250 or 25 °C above the normal maximum operating temperature. Do not exceed column maximum temperature. To bake out the GC inlet see How to Bake-out the Split/Splitless Inlet (S/SL) on Agilent GC Systems .

7. Hold at temperature for 30 minutes 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

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

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

10. Check the FID output value. It should be lower than the first reading.   

Learn how to effectively operate your Agilent GC Detector:  GC-0GEN-1013s - GC Detectors Theory and Operation  GC-7890-1250s - Agilent 7890 Flame Ionization Detector (FID) Theory and Operation e-learning courses available from Agilent education.