Hi, I am a Ph.D. student. I am working with GC-IRMS. We have MAT 253 IRMS along with Ultra trace GC. and GC interfaced with IRMS through GC combustion III. Recently I had a problem of really high water background after doing maintenance e.g. changing the oxidation catalyst and replacing the septum and liner. However, other backgrounds, e.g., Argon and nitrogen were ok. I tested the instrument for leak check but could not find any leak with Ar gas. After two days, over the weekend, the filament (box and trap values) turned to be zero. I suspected that the filament was broken and we replaced the filament. after replacing the filament, we turned on ion source again after some time, and box ad trap values showed up again. but unfortunately, it went to zero again after 2 minutes. Now this process is continued of showing up of box and trap values and turning off in 2 two minutes. We changed the nafion membrane two years before. did someone face the same problem? or can someone suggest any solution regarding this? I would be very grateful.
hello in my opinion it is an electronic problem, see the current source and the electronic box! I had a similar problem on IRMS-ISOPRIM
Good luck
Hello. i have been using EA-IRMS for many years. After source maintenance, it can take up to 2 days for the device to be conditioned. The limit value for water is 4000 on our device, but I have not seen it go above 1500 after conditioning. Nevertheless, the first thing to do in cases where the water value is high is to replace the water trap. If the situation does not change, the second thing to do is to heat the GC column for a short time (the temperature value and time to be reached varies according to the device. it may be written in the manual). We also experienced recently that the box and trap values were 0. The electrical connection parts of the source may have come out of place or there may be a problem with the filament. We had the same problem with 2 different filaments. The problem was solved with the 3rd filament I installed.
@ Özge Erdem thank you for your response. When the filament current (box and trap) turned out zero in your case. Did you only change the filament or also did something regarding the electronics?
Issam Moussa Thank you for your response. Can you tell me how did you fix the problem in your case?
J'avais envoyé le boitier électronic pendante le mois d'aout pour le diagnostique et la reparation
je suis actuellemnt retraité mais si ma mémoir est bonne c'était le courant d'alimentation à découpage en DC
I had sent the electronic box during the month of August for diagnosis and repair
I am currently retired but if I remember correctly it was the DC switching power supply
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