How to diganose water leak in GC-MS?  15% water, 7% nitrogen.

Hello,

I pumped down a GC-MS (7890B/5977B) overnight and I continue to get a high water reading.

My air check readings are as follow:

water: 15%
N2: 7%
O: 2%

The 7% N2 is typical for our system since the inlet is connected to the headspace unit, but I am unsure of the high H2O reading.

What's the most likely causes for high H2O, normal N2 reading?

Parents Reply
  • Is it only Nitrogen in the background?  What is the Nitrogen to Oxygen ratio?   Dry air contains 78% nitrogen and O2 is 21%...so it looks like ~4:1 ratio.  If there is Nitrogen but no, or little, oxygen, then either there is nitrogen in your gas supply or a leak before an oxygen filter that is removing the oxygen.

    Please share back a screen capture of the air/water check and a current autotune report, too.

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