Chromatography Forum

In addition to source cleaning be sure to use bake.mac to bake out the source and quadrupoles for 8 hours afterwards.

Hi all, on november 6th I finally found the problem and fix it! (Sorry for the delay in my post, I had a lot of job to do after fixing the problem)

First, there was way too much oil in the diffusion pump so I emptied it to the right level. Also, in the method I found that the helium flow was way to high for the diffusion pump... The analyst who was using the GC-MS was running with a 3mL/min flow. I made him use a 1.4mL/min flow and everything came back to normal.

Thanks a lot to all of you for trying to help me with this baffling problem!

[quote="MSCHemist]
Oh I've been interested in asking how do you like the No-Vent system. I work with the Agilent Quickswap and found it to be a nightmare to get to form a seal on the transferline. Does the Restek system work well. I am getting a 6890/5973 for the plant and thought it might be a nice add on.[/quote]

I think the EZ No-Vent works well, it saves us a lot of time when switching methods which would need to take overnight to stabilize if we had to open the MS. We switch methods often, we have to use maybe 2 or 3 EZ No-Vent a year because ferules get stuck in it or the screw get ripped cause we have to tighten the nut often to avoid leaks. Even with the column installation tool, it is not easy to get the right lenght for the transferline.

I don't know about the Agilent quickswap but I think EZ No-Vent saves us a lot of time so I wouldn't exchange it to go back to venting the MS whenever you need to use another column... The only big problem that we had with this system was that we forgot to order different size of ferules...

I would recommand the Restek EZ No-Vent for sure even if I was a little bit negative in the end of the first part of this message!