Discussion Category: GC-Tandem MS
High Nitrogen. HELP!!
Hi there
I have been having a problem with a high Nitrogen peak when doing my Air/Water checks everyday. So I went about checking all possible leaks from the gas cylinders outside, all along the pipelines by tightening the nuts and went all the way to the injector part and the column, replaced the inliet liner, septum and o-ring as well. When I ran the check again I found out that there Nitrogen was still high. One problem I had always had though was that the screws that hold the ion source housing were not tight 'cause the threads go worn out somehow, so all along the source housing was held down by vacuum. I made a pad support to push the housing down as an experiment to see if the leak would decrease and amazingly it did, to a very low number. That worked for a while and a colleague of mine came in to repair the threads so we expected the machine to maintain that Nitrogen level now that the housing was appropriately being held in place. The morning after the repairs the Nitrogen had gone up again so i left it for the weekend and hoped it would get better and when I did the report this morning I found out that it is still up.
I cannot really think of anything else to do now, I have done a bakeout.......and most things that I could. The only thing that is faulty now is the foreline pump. It leaks but not so much. Could it be the problem perhaps? Please help
Thanks in advance