FID Inlet Clogged/Blocked on 6890N; Need Advice

Discussions about GC and other "gas phase" separation techniques.

19 posts Page 2 of 2
MichaelVW wrote:
What is it about the weldment that you think might be broken? (Sorry if I missed it in one of the older posts). Did you take the collector apart like in the link ConsumerProductsGuy shared?

I know you mentioned being reluctant to, but honestly - just don't throw it against the wall. They're pretty decently sized metal and teflon pieces, nothing super delicate imo. I'd be way more comfortable letting someone new to the instrument do that part than having them install a new weldment.


No, I did not take the collector apart. The opening of the weldment (at the bottom) has a hole that is supposed to allow a capillary column to pass through, but I think someone had previously tightened something too tight and caused that hole to shrink in size. It appears as though a ferrule got jammed in there and mushroomed the surrounding metal parts to make it smaller. A paper clip does not pass through as it should according to agilent's site. The collector isn't the issue as the issue is in the injections not getting to the jet. I brought it to the machinery department and we tried hammering it out (thinking there was a ferrule stuck in there) but ended up bending every small tool we had (even with tubing support). We also tried drilling it from the bottom, but it just melted and damaged the drill bit.
I am ordering a new one from Restek. The steps to remove/install the weldment really are not that complicated at all (I followed a manual provided by Agilent). I just feel there is really no other option besides getting a new weldment to alleviate the problem. I would like to point out though that the same part is like $1,600 on Agilent's website while Restek is only $600. That is a huge price difference. I called Restek to ask why this would be the case or why I should go with one or the other and the assured me that I could return the part if it didn't work and that It would be fully compatible with the 6890 fid gc.
Yikes, guess that answers that. And yeah, Agilent's prices can be... creative. My favorite so far is $112 for a nine-pin serial cable.
MichaelVW wrote:
Yikes, guess that answers that. And yeah, Agilent's prices can be... creative. My favorite so far is $112 for a nine-pin serial cable.

Oh my gosh, that's ridiculous! yeah creative is one word I would use lol.
So a follow up to conclude this thread...

I installed the Restek Weldment part on my GC and so far so good. The capillary column was able to move smoothly through the opening to the mouth of the jet without any issues. I let my GC vent overnight and I will confirm if this solved my issues I was seeing in terms of leakage and variability in analysis.
Thank you to everyone who helped me along the way with this. It was greatly appreciated!
19 posts Page 2 of 2

Who is online

In total there are 2 users online :: 1 registered, 0 hidden and 1 guest (based on users active over the past 5 minutes)
Most users ever online was 1117 on Mon Jan 31, 2022 2:50 pm

Users browsing this forum: Google [Bot] and 1 guest

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry