Thank you for the help, here is a summary of the responses I received. I did not include all of them as many were basically the same, but I appreciate the overwhelming response to my question. These will go into a file so that if this happens in the future I will be able to look back on this and learn. I hope it may help people in the future. If anybody wants more of the responses, please mail me individually and we can go from there.
Margaret
The “cleanest” way of ensuring you get all the glass out is to remove the probe and drop the lower shim stack from the magnet.
I’m assuming the system is a 5mm Hi-Res instrument, in which case removing the probe will allow you to look directly into the top of the probe to ensure no tube glass has found its way into the probe. If there are fragments of tube in the probe you may be able to remove them by simply turning the probe upside down – if that doesn’t work then dismantling the probe is your only option which, although not that difficult, is not for the faint hearted especially if the probe is a gradient version. Make sure you mark the alignment of the probe before removing it as there are 3 sets of orientation screw holes
Equally, removing the lower shim stack is not that difficult but it is a 2 person job. First thing again is to make sure you mark the alignment before doing anything else and make sure you use non-magnetic screwdriver. It’s also worth putting the cap into the top of the stack or plugging with paper towel if you don’t have the genuine cap. Then just loosen the 3 recessed screws on the top of the upper section and the lower section should slowly drop down – it will not drop out until all 3 screws are fully undone. Don’t disturb any other clamps etc. on the top of the upper section. Any broken glass will be sitting on top of the spinner jets so will come out with the lower section. Reassembly is the reverse of removal and the securing screws will be pushed up as the lower section is inserted & drop slightly when the alignment is correct.
You may need to do a small amount of re-shimming after this but nothing should be too far out.
The shop vac idea will work with a couple of caveats. The first is obvious – whatever goes in the magnet (hose, tubing) should be non-magnetic. I did this with the stainless J tube once when I had Ice block the charging plug so it was also at 4K. The second is you do not want to be vacuuming organic solvent vapors. They are flammable and if they get to the vacuum, there is a chance that there will be an explosion when the vapors hit the electric motor. I suspect that if the solvent was organic, it has probably evaporated by now and the amount was pretty small, but that is something to be aware of.
The first thing that comes to mind is to remove the probe, and then go fishing (from above) with a copper or aluminum fishing rod and copper wire, or sticky tape. I use an aluminum tube that came with our Varian for use in N2 fills (ID ~7mm). You can put tape on the end and try that first. I have had success by threading a copper wire through the tube, making a loop in the end, and snagging an end of the glass tube, then pulling the wire tight against the end of the aluminum pipe and retrieving. It's not easy. You have to be above the magnet to look down the bore as you fish, flashlight in one hand, fishing rod and line in the other, or some such configuration.
With the probe out, though, you may just be able to knock the NMR tube loose and let it fall out. I don't know your 300 model, but if you are concerned about small pieces of broken glass you can always just pull the whole VT stack. Your vacuum may work as well. Can't foresee any issue there. The worst that could happen is you burn the motor. You could also attach a small brush to a piece of tubing and try to clean the stack. There shouldn't be many surfaces for particles to rest on, once the probe is removed.
First, don’t panic. This has happened in most NMR labs at one time or another. The way I have handled it is this.
First remove the probe. Older Bruker probes, at least the ones I had, without pulsed field gradients, can be easily disassembled, If there is any chance that broken glass is inside. The outer sheath is screwed to base, and to the probe internals with very tiny screws. After removing the screws, lift the outer sheath straight up SLOWLY. There are glass and ceramic pieces that are not glued in place. Coils are not glued to the glass pieces. Clean and reassemble as needed.
The upper stack is held to the shim coils with three LONG screws. Before disassembling the stack, use a fine tip sharpie to mark the level and rotational orientation of the upper stack and shim coil on the collars that hold them in place. Find a helper to hold the shim coils while you undo the screws. Do not remove the long screws from the upper stack. It is very difficult to reinsert them. Remove the upper stack from the top and the shim coils from the bottom. Clean as needed, and reassemble.
From: Smallbrock, Margaret A. [mailto:Margaret.Smallbrock_at_sdsmt.edu]
Sent: Tuesday, March 13, 2012 1:07 PM
To: ammrl_at_ammrl.org
Subject: AMMRL: Broken NMR tube in NMR - Help
Greetings all,
I have a Bruker AC300 NMR. This morning, one of my users broke an NMR tube in the NMR. I can see the tubes lying at the bottom of the sample stack. The spinner is not in the magnet, just the remains of the tube lying across where the sample drops through into the shim coil. (I believe this is the best way to describe where it is)
I am trying to determine the safest method to remove the broken glass from the system. I found both the top and bottom of the tube and the pieces at the bottom appear to be the right length to have not shattered into tiny pieces. I have a Shop Vac that has a 20 foot hose that I can park in a corner away from the system. I was considering adapting tubing that would fit into the sample compartment to capture the glass. I however did not want to attempt it without vetting the idea with people that are far more knowledgeable about NMR in general than I am.
Any suggestions on how to remove the glass would be very helpful if my initial idea is not a good one or if you can provide ideas to make it a better solution.
Thank you all,
Margaret Smallbrock
Margaret Smallbrock
Chemical and Instrumentation Specialist
Department of Chemistry
SD School of Mines
501 East St. Joseph Street
Rapid City, SD 57701
(605) 394 - 1236 - Phone
(605) 394 - 1232 - Fax
Received on Thu Mar 15 2012 - 06:44:14 MST