Howdy Everyone,
    I am soliciting suggestions and ideas for an hydrogen source within our mass spec.  We've been having an ongoing mystery concerning a large amount of H2 in our 252 since an inlet venting failure.  To make a long story very short:  

The cause:
-We have 120V scrolls as the backing pumps, which means when the inlet vented, the scrolls never turned off because they are not a function of the 230V inlet power control switch.  Therefore, it was believed that the oil from the wasteline Pfeiffer turbo felt pads had contaminated our machine with hydrocarbons since it was under vacuum for some time, and hence, our H2 problem.

The solution:
-Subsequent B scans confirmed hydrocarbons, and we baked out the entire machine; source, COV, and inlet (but not the flight tube).  

The mystery:
-After the bakeout, the hydrocarbons were all but gone, our 252 had a clean bill of health.  Then we added standard gas, the H2 returned but NOT the hydrocarbons.  (The standard gas was proven to be hydrogen-free).

Troubleshooting steps:
-It was thought that perhaps we baked ON the oil, so we changed the capillaries to be sure.  This has made no difference.  
-Next steps might be to bake the flight tube, although a longshot, since we analyze only N2 and Ar.  
-Rebuild and clean the COV

The issue is there is too much interference going on from the hydrogen, which affects our 29/28 ratio and the subsequent statistics prove this to be true.   Does anyone have experience with this kind of problem?  Many thanks for your time.