Chromatography Forum

I have GC/MS system (GS 3900, MS 2100T) from Varian.
Instrument has not been turned on for at least 2-3 years.
MS always shows NOT READY status, when come to autotune and check for air/water leak.
AIR shows OK, and
WATER show Massive (19/18 ratio shows 150-200%).
When I Bake it Out for 2-3 hours it still similar 19/18 ratio %.

What to do?



Please, URGENT!

Wait one night and if it is still not ok isolate the MS from the inlet (plugging the column) and see if it improves..

you mean leave it on bake out mode all night long if I understood correctly?

Leoglag,

I've seen that you have an iontrap. I admit I have experience only with single quads.
Nonetheless with single quads you have to wait quite some time if pumped down after a long period (>12h, especially old models). I don't know the typical parameters of your system (I mean source T, etc.) Just use those and wait. If the water doesn't go down it might be carrier gas contamination. If that's the case, plug the column and see if the water decreases.

Good luck.
bhuvfe

There are actually two points in this solution.

First thing I observed that carrier gas is connected to O2 / H2O filter which was way to saturated (to old, spent out), but I found a new one and replaced it. Right after that water level was "just" High (not massive anymore).

Second thing I did was, of course, "Baking out"! I used the temperatures of Trap, Manifold & Xferline, 170, 80, 220 °C respectively and left in "Baking mode" for I think 14-15 hours over night, after that all selftests went fine and I was able to do first measurement after quite some time, which was great.

Thanks bhuvfe for help.

Before this system I had hp5980, i think, wich broke down, so I need to learn again how to work on varian.

Next problem now is to read result after the analysis.... I couldn't get it to compare analysis results with nist database, I'm not sure what to do first after analysis is done to compare it with database........ I'll all of it again in a two week time.