GC 7890B Leakage with graphite O-Ring (5180-4173)

Hello everyone,

As I want to run a higher S/SL injector temperature on my Agilent 7890B GC (approx. 320-360°C), I wanted to replace the previous Viton O-rings with the Graphite O-rings. Unfortunately, I can't get them to seal using the normal installation method.
In fact, the injector is so leaky that it can't even reach 10 psi inlet pressure. If I change back to the Viton O-rings, the S/SL injector is perfectly tight again.

Any tips/experience on this?

Many thanks in advance.

Parents Reply Children
  • Norbert, thank you for your answer.

    I am very sure that it is not due to too much pressure. As the graphite O-ring still looks good afterwards and there are no deformations or cracks. I also only screwed it on very lightly on the 2nd attempt and then observed the inllet pressure and only then tightened it again and checked the inlet pressure further.

    The metal surfaces also look good and there is no damage to be found.

    Liner: Single Taper Splitless Inlet Liner, 4.0 mm x 6.5 x 78.5 (Restek 22406)
    O-Ring: Inlet liner O-ring, graphite, for splitless liner, 9.63 mm od, 6.52 mm id seals (Agilent 5180-4173)

    Should therefore also be compatible with each other.

  • All seems to fit, then it will be difficult to give advise from a distance. Maybe some of my instrument colleagues can give you some input

Was this helpful?