Small air leak 7010 GC-TQ


I am looking for some advice on how to troubleshoot a small air leak in a 7010 triple quad. The leak is small enough that using an an air can at several of the check points can't detect a leak. So far I changed the side plate o-rings, vent valve o-ring and reinstalled the column. We have a second GC-TQ that shares the same gas cylinders (although that one has a universal gas trap) which easily passes the air/water check, although the one GC-TQ in question just barely fails the nitrogen/oxygen criteria.

Any suggestions would be appreciated.

  • How small of an air leak? From the air/water results on the autotune report or from an air/water check in Manual Tune?  Would you be able to share a picture of the test results?

    And keep those old side plate O rings, they are probably fine.  When you changed them, did you clean the grooves with a solvent wet swab? Did you wipe the analyzer side plates with a solvent wet lint-free cloth?

    Which column ferrule and column nut are you using on the inlet and transferline?  Could the leak be at the inlet instead of the MS?

    What is the column flow?  The HES is very sensitive to column flow differences. What is not a leak at 1.0 ml/min will look like a leak at 1.4ml/min and look like a big leak at 2.0 ml/min.  So if you are trying higher column flows, reduce it to between 0.8 to 1.3, tune it, and see if that helped.

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