Chromatography Forum

I have been using my HP 5890 for a few years now but am still a novice. I decided it would be a good idea to clean my FID, seeing as I never have, and am now running into problems. I will let you know what I did and what I have done to attempt to fix it.

I took it apart, cleaned the inside of the collector with a clean cotton swab, inspected the jet, which was actually pretty clean, and reassembled it. I started the machine and ran a standard and nothing showed up on my chromatogram. The flame was in fact lit (checked via condensation). I then took it apart again and was concerned that maybe I had damaged the jet (at this point I realized the removal tool in the GC drawer that I had used was not the correct one) and inspected it under the microscope. It appeared that the top had in fact been smashed a little.

I since purchased proper cleaning and proper FID removal tools and a replacement FID. I reinstalled everything but with the replacement FID, but when I ran it again, my chromatogram still read 0. And yes, the flame is once again lit. I am guessing the spring is not in the right position, but can't really tell what I am doing wrong. Also, at this point I am wondering if the spring is damaged. I am perplexed right now and am not sure exactly how to fix it.

I'm hoping this is an easy fix for all the experienced people out there. I am using a glass packed column for short chain VFA analysis (if it matters).

Thanks, Josie

Is electrometer turned ON [DET] [A] [ON] or [SIG] [A] [ON] ?

I think the detector is in fact on. I reassembled it again and used a stretched out paperclip to make sure the spring was in the groove. I am now getting a response but the same mM standard curve is coming out with less area than before.

Check if the jet is the correct one for packed columns.
Packed column jets have a wider orifice so the flame is different.

I purchased a replacement jet and reassembled the FID. The spring is very challenging to get into place and this time I used a paperclip to help me wiggle it into place. So far, things seem to be working. Thanks for the ideas!