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- Posts: 11
- Joined: Fri Jul 01, 2022 5:22 pm
I am an undergraduate researcher and I've had about a years worth of experience with gas chromatography. I am currently operating a Agilent 6890 N GC. I have run into some issues of late and was wondering if anyone has any advice for me.
Essentially my issue consists of the following details:
- I was observing variability in FID readings as if I had a leak somewhere. I checked all feed lines and found no Issues and determined it must be within the GC. I preformed the leak check that Agilent recommends on YouTube, and found that the leak consisted somewhere from the front inlet to the FID. After tightening pieces and working my way down I came across the connection between the column and the FID itself (downstream on the column respectively).
- When I gave the column a slight tug it fell right out of the connection (hence I deduced the leak was there). But my problems got worse... As when I removed the fitting that connects the column to the FID through the roof of the oven, I noticed the graphite ferrule had been completely obliterated(smushed to a flat top and unable to see through).
- From the Agilent manual I realized that the capillary column is supposed to slide approximately 48mm through to the FID Jet. when I attempted this it would not even pass the beginning and when I removed it, appeared like I had gotten graphite and pieces of glass on it. I thought that this likely indicated that the FID jet was clogged and I reviewed steps on how to remove and clean it.
- Following removal of the FID jet it was found that the jet wasn't the problem at all (I could see clearly through it when shined up against a light and acetone passed smoothly though it). When I shone my torch from my phone through the oven however, I was unable to see the light. Hence I thought that maybe the actual inlet piece was clogged or had pieces of a ferrule/column stuck inside.
- I tried removing a segment of column and using that to poke the clogged material through from the top down. This did not work so I instead turned to a 0.4mm 3D nozzle needle to poke the junk out. This did work, and I saw broken pieces of column and pieces of graphite falling to the ground. (I of course rinsed the needle with acetone before beginning this procedure to avoid contamination). Throughout this procedure I used a flashlight underneath to view exactly what I was poking out until it became clear there where no more contaminants in the path line.
- Following proper reinstallation of the FID components, I tried to reinsert the column back through the FID Inlet, but to no avail. It seemed to still be clogged. I do not know what to try next.
Thanks,
I was unable to attach the image. any help with that too would be appreciated. let me know if its even necessary.