Chromatography Forum

I think a blockage in either FID jet would cause longer retention times in both columns. If you have spare FID jets then I would try replacing these, it is easy and quick. If that doesn't work can you post chromatograms from both FIDs, before and after the problem started?

I think a blockage in either FID jet would cause longer retention times in both columns. If you have spare FID jets then I would try replacing these, it is easy and quick. If that doesn't work can you post chromatograms from both FIDs, before and after the problem started?

Thank you for your suggestion...

I can't replace the jets because I haven't spare but I will clean them. This week, I will try clean them, when I will do I will comment that has occurred.

I will write as soon as possible!! Thank you for your help...

They can be difficult to clean, so sonicate in water then methanol, and try to poke out the orifice with a small wire, I know a guy who uses a strand of a guitar string. You really need spares of these jets, if you swap one good one for another then you can just keep it as another spare, but the down-time of waiting for an order is too long, and clenaing doesn't always work.

When the FID peaks are becoming even more delayed over time, what is the peak shape like? Are the peaks becoming wider?

maybe you need trim the column which is in the detector side.

Thank you very much for your help

Yes, the peaks were becoming wider and fatter. The solution has been to change the column.

Hello!

In my laboratory, we have two gas chromatograph 7890A. Now, the problem I have in the other chromatograph 7890 A (not in the chromatograph where I observed the movement of chromatographic peaks).
Now, the problem is that in the middle of a sequence, the FID turn off. I think that the problem aren't the air and the H2 because if the problem were these gases two FID shut down.
In this gas chromatograph, we have two FID detectors.

Please, help meeeeeeee!! Thank you very much!!!!

A clean detector that has good gases set at the proper flows, having no defective parts, bent or blocked, will not fail to maintain a flame.

Would this be the GC that had the bad column? (which may have bled deposits into the FID?)

Start cleaning and checking your parts.

best wishes,

Rod

A clean detector that has good gases set at the proper flows, having no defective parts, bent or blocked, will not fail to maintain a flame.

Would this be the GC that had the bad column? (which may have bled deposits into the FID?)

Start cleaning and checking your parts.

best wishes,

Rod

This GC isn't that had the bad column. It´s another GC 7890 A, but I think that first I would have to clean the FID jet???

Thank you very much for your answer!!

A good place to start.

Rod