Chromatography Forum

Hello.
I am in the process of chasing down leaks on my HP5972 mass analyzer. The analyzer seats on top of an oval-shaped gasket, which is seated on top of the main chamber. The system pumps down fine, but air/water checks routinely come up with high 28/69 ratios (last one was 49%). When I run a scan and spray "dust-off" (office depot, HFC134-A, m/e~33, 51, 69, 83) signal rapidly appears when I spray the area around the gasket, near where the transfer line comes in. (This is after having vented the system, cleaned the gasket and surrounding area with IPA, and reseated it). When I put the cover back on the analyzer and spray other locations (Xfer line, Xfer line-column connection) no signal appears. (Leak tests were done with the injector port blanked off, so these leaks are discounted). Any ideas? Might the gasket be upside down?

Rich

Hello!
Use Argon for detect leak, that's the best and scan mass 40....gasket leak often..when i open the side door, i apply a small quantity of grease APIEZON L #Agilent#6040-0289.
It is possible that your O-ring for Vent valve is so tight too or dry...change it

Yes! You are right for Checking method of gasket. the gasket contaminated or attrited will make leaking. It is the better to replacement the gasket. I think maybe well if you make gasket upside down,you can try.
good lucky.

Remove the gasket and apply some high vacuum grease to it. Use a kimwipe or similar and wipe off the excess grease. Then re-seat the gasket. Make sure that the contact area on the analyzer is clean. Should seal up well.

Also check to make sure your column didn't break. I've chased a leak similar to what you're describing and eventually found that I had a broken column (The break was in the middle of the column and that pretty much wasted it).

The dust off method works great for leak detecting