Chromatography Forum

Hey all, I recently lost all peaks/Sensitivity on my last sample run. I noticed the FID had gone out, i took apart the detector thinking i would have to clean the jet, but i saw that the gasket was torn/chipped, not all the way through however. So I have ordered new gaskets from agilent but they won't be here for a couple days. Are there any replacements that are more common to use (hi temp ones?). Also when these gaskets do get old, is it hard to re light the FID? Just wondering what everyones experience with them is. Thanks.

The Agilent 5890 FID gaskets last a long time. Yes, any leaks in the FID will make lighting the FID tougher, as will a partially clogged FID jet. You can try blowing gently onto them as you try to light. Also, loosen/tighten the ignitor itself and the mounting screws to ensure good electrical contact.

Hi, just an update. I don't think the seal was the probem. We have a leak somewhere in the FID. I can get the GC lit, but i have to turn the Air psi all the way to 0 and then bring it slowly back up to 42 psi (400ml/min) if i try to do it fast it will flame out.
Also I have now lost all flow from the column through the FID. I have confirmed bubbles are rapidly coming out of the end of the column in methanol.
I have checked the column nut and 1/4" nut and confirmed that there are no blockages, the ferrule seems to grip the column tightly in the column nut.
I have made sure the jet is cleaned and light can be seen through it and i have taken a wire through the opening of the jet.
I just don't know where else there could be a leak/block. Thanks

It sounds as if you have a flow rate problem - too high a flow of make up, air or carrier, or too little hydrogen. You need to measure these with a flow meter, do not trust the readouts from the GC.

Peter