hypervalent_iodine Posted July 4, 2014 Posted July 4, 2014 I'm wondering if anyone here uses or has used a Thermo GCMS before. We have a Trace1310 in one of our analytical labs that is giving us some hassle with a weird leak. I'm a bit of a novice with the more advanced aspects of GCMS maintenance, etc., so I'm struggling a bit to try and figure out what is going on. The story is this. Yesterday we had a software problem that prompted one of my colleagues to turn off the GC component at the switch on the back of the machine and reset the computer. This fixed the software issue, but since then we have had a huge gas leak appear and I'm not sure where it's coming from. This is a screen shot of a water/air scan I did (there is no change with the cal. gas being on or off): And the most recent tune from today: There is clearly an issue given the amount of oxygen, nitrogen and argon (and whatever the peak at 27.7 is). I have replaced the septum, but it did nothing to fix the issue. No one has played with the column or any of the connections, which I have found to all be fine and not loose. The carrier gas tank is also fine (our Shimadzu runs off the same He tank and is having no troubles), so it's not from that. I am wondering if turning off the machine at the power lever has turned off something else in the machine, but I have no idea what and the manual is of no help. I've also emailed our rep, but he is apparently on holiday for two weeks.
CharonY Posted July 4, 2014 Posted July 4, 2014 Seems very indicative of a leak. While it is odd that fittings should be loose if no one touches them, it sometimes happens (especially when the instrument cools down). I would go through that again in more detail, check proper seating of ferrules etc (typically column -> MS is the culprit). And once everything is secured run another air/water check. If that does not work you may have to use more elaborate approaches (i.e. aerosols or capping off parts) to find where it is.
hypervalent_iodine Posted July 4, 2014 Author Posted July 4, 2014 I managed to get a hold of a Thermo rep late yesterday who has confirmed my suspicions that this is a particularly weird leak, wherever it's coming from. The air/water check I ran was actually after everything was tightened and resetting everything has also not helped at all. I'm mostly confused about how there is so much oxygen. If it were an air leak, I would have expected to see a 3/4:1 N2:O2 ratio and yet somehow I have about twice as much oxygen as I do nitrogen. There aren't any traps in the machine that I know of, so it has me stumped. I'm going to blank out the MS Monday to see where the problem is. I'm kind of hoping it will magically fix itself over the weekend.
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