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Thermo GC-MS/MS
Posted: Thu Jul 31, 2008 8:41 pm
by yangz00g
Any one has experince with Thermo's Trace GC Ultra-TSQ MS/MS? We had one installed recently, but is experiencing some high N2 signal (comparing to H2O signal, H2O/N2 ~2:1.2 to 1.3) during the turing process. The vacaum is very good. Anyone sense there my be a leaking? Thanks in advance.
Posted: Fri Aug 01, 2008 9:20 pm
by Ron
What is the ratio of nitrogen to oxygen? If it about 4 to 1 you have an air leak. I suspect the ratio will be much larger, around 50 or 100 to1.
Do you have one of the Valco traps on the carrier in line? These often release a large quantity of nitrogen when first installed, and this lasts for a long time if the trap in not mounted vertically. If you have one of these traps try running at a 250:1 split for 20 minutes and see if the nitrogen goes down.
Posted: Wed Aug 06, 2008 3:28 pm
by yangz00g
Thank you very much, Ron.
The N:O ratio is around 3:1 consistently. There is a N-pretreated filter in line, but have it purged for quite a while.
The mystery is when it's operated at 1ml/min, N signal is at normal range, but when flow rate is increased to 2, N become abnormal. We have a thermo technican here struggling. The answer is likely to be "no problem".