Chromatography Forum

One of my colleagues was replacing the column on the GC/MS yesterday. When he was removing the column from the GC/MS interface assembly, the graphite ferrule broke into a few small pieces, and through some terribly bad luck, a piece of the ferrule fell into the interface.

It is now completely stuck. I have been attempting to dislodge this piece of graphite by running a small diameter wire from the detector side to push it back out with absolutely no luck.

I believe that the reason why it is "stuck" is because my colleague attempted pushing the piece further into the assembly with hopes that it would come out the other side.

I think the assembly may have also still been warm when this occurred, so perhaps some interface shrinkage is holding it in place.

Questions: does anyone have a suggestion for how to get this piece of graphite out?

Am I going to harm the interface by attempting to push the piece of graphite out with a similar diameter wire?

Do you think that heating the interface up before attempting to push it out is worth a shot?


Thanks very much for any help that anyone is will to offer!

Must be a pretty big chunk. With the source open to atmosphere, can you just blow it all the way through with some air? How about sucking it back the way it went in with a vacuum pump?

Is the "interface" the transfer line - the fat tube with a column nut on one end and a connection to the body of the MS on the other ?

If so, then remove it from the MS body, take off the column nut and poke the graphite out from the MS end. Try with an odd piece of silica column - stiff, straight and the right diameter.

I thought that graphite was not recommended for transfer line connections because of the risk of sucking a fragment of electrically conducting graphite into the high voltage electrics of the MS ?

Peter

Is the "interface" the transfer line - the fat tube with a column nut on one end and a connection to the body of the MS on the other ?

If so, then remove it from the MS body, take off the column nut and poke the graphite out from the MS end. Try with an odd piece of silica column - stiff, straight and the right diameter.

I thought that graphite was not recommended for transfer line connections because of the risk of sucking a fragment of electrically conducting graphite into the high voltage electrics of the MS ?

Peter

It definitely should be graphite/vespel and not pure graphite on the detector end of the column as graphite is also too porous and will not completely seal against vacuum there along with them being fragile. On the other hand I have also had the graphite/vespel ferrules break apart like mentioned above.

I don't know if the small diameter tube inside the interface is removable on the 5973/5975 like it was on the 5971/72 models so it may not be as easy to take out that small tube and clean it. A wire should work to push through from the detector side, or maybe even a piece of 0.53 column will work. You could also squirt a little methanol in there to try to lubricate the stuck piece of ferrule.

Unfortunately I have experienced the same problem several times both with a 5973 and a 5975. In both cases what worked for me was first to remove the transfer line from the MSD and then push a wire from the detector side using pliers. Sometimes you have to use much more force than what you’d think would be necessary. One piece of advice, grab the wire with the pliers as close to the entrance of the interface as feasible when pushing. As I said before, sometimes the plug is firmly stuck and it is essential to push determinedly; the force applied can bend the wire and a crooked wire is no longer useful because it would not slide further into the interface.
Good luck

If it is the transfer line, we had a lot of success with a wire guitar string. It must have been a D or G, because it was a wire-wrapped wire. It is nicely stiff, a good diameter, and there is a lot of it. We would run it in from the detector side, sometimes wetted with Methanol.
Good luck1

The stainless steel sparge needles from a purge and trap have always worked for me in this case. I think ~ 1/16 inch OD peek tubing will fit nicely as well.

Thanks everyone for the replies. I have been out of town for the past week or so, but I have returned and no one has been able to fix the problem. I have been pretty gentle with it thus far, but I am about to increase the amount of force. I have been using a steel wire that is almost exactly the same size as the internal diameter of the "welded interface assembly."

This is the part that is clogged. When fully assembled, it has a heating element wrapped around it.

The clog seems to be very stubborn, but I will try previous suggestions. If anyone else has other suggestions, I'm definitely open to them!

Update: I fixed it. Just needed to quit babying it. Thanks everyone for the help.

Heat your interface (200c) for metal expansion...try with Megabore column or metal wire to push the ferrule out of interface....from inside of MSD to oven
If you have no success, connect gas line to interface and increase pressure..maybe, ferrule will exit form interface.....you can discinnect interface form MSD too.

Unfortunately I have experienced the same problem several times both with a 5973 and a 5975. In both cases what worked for me was first to remove the transfer line from the MSD and then push a wire from the detector side using pliers. Sometimes you have to use much more force than what you’d think would be necessary. One piece of advice, grab the wire with the pliers as close to the entrance of the interface as feasible when pushing. As I said before, sometimes the plug is firmly stuck and it is essential to push determinedly; the force applied can bend the wire and a crooked wire is no longer useful because it would not slide further into the interface.
Good luck

I had the same problem today and I was about to have a panic attack. Hopefully I read what Carras suggested, and with a help of a small diameter wire, I pushed it through the mass detector side of the transfer line, using pliers as close to the entrance as possible. Initially I was afraid of damaging the line, but like Carras said, we need a bit more of force than we think.

Thanks for the advice

Hi Biochemist87

I am glad it was of use to you.

I'd like to post a question for the forum. I have been using Agilent interface ferrules since always and I had never experienced this until about 5-6 years ago. Has this been your experience? any ideas about the cause(s)?

Hi Biochemist87

I am glad it was of use to you.

I'd like to post a question for the forum. I have been using Agilent interface ferrules since always and I had never experienced this until about 5-6 years ago. Has this been your experience? any ideas about the cause(s)?

I don't know about the Agilent ferrules, we use the Restek Graphite/Vespel ones and I have never had one come apart unless I got over zealous and torqued them down way too tight. By then the nut usually squeaks as you turn it and it just means you need to look elsewhere for the leak