Chromatography Forum

Hi everyone,

It was an ordinary day in the lab, I was switching out a presstight on the column after a leak check. Then a gasoline-like smell hit my nose and I look up, black goo was gurgling out of the injector port. This is a Trace GC ultra. (pictures attached)


https://imagizer.imageshack.com/img924/994/2ulavi.jpg
https://imagizer.imageshack.com/img922/1738/MHsUJ5.jpg
https://imagizer.imageshack.com/img922/7903/eBwD6H.jpg
https://imagizer.imageshack.com/img924/5127/Z9h4RA.jpg
https://imagizer.imageshack.com/img922/2654/scuNfo.jpg
https://imagizer.imageshack.com/img923/883/8YCZBE.jpg
https://imagizer.imageshack.com/img924/4238/S8KkbG.jpg

The carrier gas was already shut off. We disconnected the column at the bottom of the injection port. We pulled from the bottom of the injector and capped it. The graphite ferrule is still in there. The column isn’t black. In fact, even the glass liner in the injector was completely clean. The septum was relatively clean too. The black substance was coming from above the septum.
The black substance isn’t what I would call brittle (although it has hardened), and it doesn’t dissolve in methanol or acetone.
The GC technicians we contacted said they’ve never seen or heard of this happening before.
There were no plastics or loose rubber near the injector at that time, so I’d like to rule out plastics getting on top of the injector.
I’ve done a search on this forum and saw a discussion on cleaning split vent lines.
(link here: https://www.chromforum.org/viewtopic.php?t=22191 )
My question for you GC gurus out there is: do these pictures look like the black substance is related to the split vent line/split vent filter not being cleaned?

Thank you

I'm not familiar with that model of GC, but I'm not sure what else it could be. I'd guess the manufacturer's manual can tell you how to change the split vent trap. If the lines are that gross, there's a good chance the trap and its housing are pretty nasty too, and that would confirm your suspicion.

I have seen something like that in an Agilent GCs vent trap doing flavors analysis. Ive also done ROIs, and carbonizing most things will give a similar product to that.