How to replace the Gold Seal on the Split/Splitless (S/SL) Inlet for an Agilent GC

This Information Applies To: Agilent 6890, 7890, 7820, 8890 and 8860 GC Systems with Split/Splitless (S/SL) inlet

Issue

Replacement of the Gold Seal is required as part of inlet maintenance. Replacement is required when the performance of the inlet degrades over time due to accumulated contamination (e.g., baseline noise, ghost / artifact peaks, loss of reproducibility, carry over, loss of compound response or no compound response).

Items Required

The following Gold seals are available

• Ultra Inert Gold Seals (p/n 5190–6144) can be used for inert applications.
• Standard Gold Seals (p/n 5188–5367) can be used regular applications.
• Cross-Cut Gold Seal (p/n 5182–9652) should be used when the S/SL Inlet total flow is set ≥ 200 ml/min.

Steps to follow

Tips: Wear clean, lint-free gloves to prevent contamination of parts with dirt and skin oils.

Tips: The 8890/60 GC Systems offer built-in guided maintenance procedures that follow the procedures described in this article. Go to Maintenance > (Front/Back) Inlet > Perform Maintenance. Select Replace Gold Seal and then "Start Maintenance". This feature resets the EMF counters automatically when completed.

Figure 1 Guided Maintenance procedure for 8890/60 GC Systems

1. Cool the GC Oven (set to 35 °C), set Inlet Temperature Off, Detector Temperature can remain unaltered. 

   Warning: The oven, inlet, and/or detector may be hot enough to cause burns. If the oven, inlet, or detector is hot, wear heat-resistant gloves to protect your hands.

   Caution: If using a TCD the filament in the TCD will be damaged if exposed to air while hot. To protect the filament, turn it Off.

2. Set the inlet pressure to 0.0 psi.

   Caution: Wait for the inlet, oven, and column to cool down to near room temperature to protect the column before turning off inlet / column carrier gas flow from the GC control software or GC front panel.

3. Remove the inlet liner using tweezers.

   
   Figure 2 Removing the liner and O-ring
   

4. Remove the column from the inlet. Cap the open end of the column with a septum to prevent contamination and air entering the column. 

   
   Figure 3 Capping the capillary column with a septum.
   1. Insulation cup, 2. Septum.
   

5. Remove the insulation cup and insulation around the base of the inlet by loosening the two screws holding it and then using a clockwise-twisting motion.

   
   Figure 4 SSL inlet insulation cup.
   

6. Loosen and remove the reducing nut. Remove the washer and gold seal inside the reducing nut.

   
   Figure 5 Removal of reducing nut.
   

7. Put a new washer in the reducing nut and place the new gold seal on top of it (flat side facing up).

   
   Figure 6 1. Gold seal, 2. Washer, 3. Reducing nut, 4. This side faces down.
   

8. Reinstall the reducing nut and tighten securely with a wrench. The gold seal  is retained by the reducing nut, which must be tightened sufficiently to make this seal gas tight.

9. Replace the inlet liner if necessary.

10. Reinstall the insulation cup and the column.

11. Reset the inlet pressure and allow the inlet and column to purge with carrier gas for at least 15 minutes before heating the inlet and / or the column oven.

12. Check for leaks by performing the Leak and Restriction Test.

13. Reset the EMF counter if needed.

    Tips: See "To Reset an EMF Counter" (7890 GC) or "To Enable, Reset, or Change a Limit for an EMF Counter" (8890/60 GCs) in the respective Operation Manual.

14. Bakeout contaminants. 

    Tips: See "To Bakeout Contaminants from the Split/Splitless Inlet" in the respective Maintenance Manual.

15. Restore the analytical method.

    Tips: This video will guide you through the gold seal replacement procedure.

Learn how to effectively maintain your 7890 and 8890 GC: Agilent 7890 Series GC: Preparing for Maintenance and Maintenance Utilities and Agilent 8890 GC Maintenance and Troubleshooting e-learning course available from Agilent education.