High Values for Air/Water Check

Question

Hello, we are having excessive levels for our air/water check after changing the gas cylinder on our Agilent 7890B. 
 H2O: 156.61 
 N2: 308419.93 
 O2: 8.38 
 CO2: 13.49 
 N2/H2O: 196939.42 
 I checked for leaks in the cylinder, changed the o-ring and septum, left it overnight at a high inlet temperature (300C), and tried running a 'bakeout method' with a solvent delay as long as the method. Still the values are excessively high. I'm not sure what else to try, does anyone have any suggestions on how to resolve this issue? 
 
 Thank you

paulsalverda · Accepted Answer

If there is high oxygen and the column has been heated up it has probably already sustained some damage to the stationary phase. Baking doesn't remove water and air. 
 Have you tried another gas cylinder? Contaminated cylinders happen surprisingly frequently. Did you replace the gas filter at the same time?

Lance Nelson · Answer

Verify that the cylinder is helium and not nitrogen. They use the same CGA fitting. If it's an air leak the N2/O2 ratio would be roughly 4.

hissingfauna112 · Answer

The gas filter was totally saturated and the cause for the high water. This issue was resolved by changing helium tanks, then noticing the water was still high, and then changing the gas filter.

High Values for Air/Water Check

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