Hi all,
Thanks to Dean, Martha, David V, Charles, Justin, Glenn, Ian, Clemens, Genevieve, David B, Justin, Bob, Ken, and Pedro for their responses.
Overall consensus: disposable economy tubes can be used and reused if they fit well in the spinner and if they are cleaned and dried properly (ie without scratching and at not at too high a temperature). SampleJet tube caps sold by Bruker (the ones with indentations for the robot hand to pick up) cannot be reused (but 5mm tubes sold for the SampleJet can be reused). There were however two less positive responses.
I assume that where diameter was not specified, 5 mm tubes were meant. Also I failed to specify that by economy, I meant disposable - I think that most people understood what I meant.
Negative (or less positive) responses:
1. Several years ago I bought a few hundred Bruker economy NMR tubes. I was very disappointed with them. Some were too tight to fit in the spinners and some were too loose. I would not recommend them. I have had very good luck with Deuterotube economy NMR tubes and I would not hesitate in reusing them.
1. When we have used these in the past we have used them either as disposable or they were for bio-NMR samples and washed only with detergent, water and 2-propanol/ethanol and air dried. No base or acid baths and no ovens.
With both the 5mm and 3mm tubes we checked all tubes when they arrived to ensure they fit the spinners. We found up to 10-15% had o.d. which was either too small or too large.
We have people here who sneak such tubes on the 300 autosampler. I test the fit and if I do not approve I will put their sample in a vial and dispose of tube. Over time the same groups have tubes with o.d. issues. I can not be certain if the tubes deteriorate (acid/base baths? Ovens?) or if they continue to buy more of these tubes despite me suggesting they do not. I think the Wilmad disposable tubes are slightly worse than the Norell ones (although I have no hard numbers to support this "feeling").
If students are careful in handling/cleaning the precision tubes they last a very long time, so their "high" upfront cost is more than recurperated.
Positive responses:
1. We re-use other Economy tubes all the time in our Bruker 60-sample cassette, the SampleXpress. No significant problems, but occasionally, one does not spin. I do tell students not to heat NMR tubes.
1. I have a research group that uses the SampleJet tubes multiple times. You need to inspect the tubes for cracks. The lids can be used 4-5 times. Once the lid doesn't fit tightly, it needs to go. The 5 mm NMR tubes can be used several times. The 3 mm are more susceptible to breakage and we've had to warm-up our cryoprobe to get broken 3 mm or 1.7 mm tubes out of the probe. We don't reuse the 1.7 mm tubes.
1. We use and re-use a lot of the Wilmad WG-1000 tubes. There aren't any special problems that have come up as a result. Probably it's not a great idea to oven bake those tubes at high temperature or for a long time.
1. We reuse economy tubes all the time. It varies widely what the students and undergrad labs are doing, but they are all using either the 4" Bruker tubes, or (primarily) Wilmad economy 7" tubes. We're not seeing any specific issues with them, although we are forceful with students to through anything out that gets a crack or chip, even if on the open end. And we regularly remind groups to dry the tubes not too hot not too long on a flat sheet. We have had a couple tubes over the last 3-4 years where the tube broke close to the bottom of the tube, and made a mess we had to clean up. It was unclear what might have happened to these tubes to have them break in such an odd way.
1. We have some groups that reuse the Wilmad version (WG-1000-8). I haven't seen an issue. I wouldn't suggest reusing the caps if you have a sample jet for obvious reasons.
1. My experience is that as long as they don't get scratched during cleaning they're good to go.
1. Yes, we reuse them all the time, and have had no issues in the 5+ years we have been using the Bruker-supplied high throughput tubes. These are the ones rated to 600MHz available directly from Bruker. The purple caps that snap on have a limited lifetime and I don't recommend reusing them with organic solvents more than a few times.
We have about 40 research groups and 150+ users who use them, so a good cross section of population, using them on instruments with and without sample changers.
1. the one thing I can tell you is that you should not reuse the caps that come with the Bruker tubes. When you cap them you can feel a slight snap. This only seals well the first time around. For reuse you should get new caps.
The general issue with reuse is cleaning and drying. Tubes should be dried at low temperatures in a vacuum oven. At high temperatures they can bend and get out of shape.
2. We use 1.7mm NMR tubes in the sample jet and it would be way too difficult to clean these tubes. Our 5mm tubes and shaped tubes are reused.
1. We use the economy NMR tubes from Norell, ST500-7 (or -8 if you want 8" tubes) and they work GREAT. The cleaning of them goes reasonably well, just depends on the cleaner's experience to be honest...
They'll develop cracks at the top every once and a while, so we just throw them away at that point. But so long as the sample is soluble in acetone or another organic solvent, we haven't had much issue.
We reuse our economy tubes and let the chemists use the washed tubes for reaction checking etc. They haven't mentioned anything specific being an on-going problem, just so long as they're reasonably dry (i.e. acetone removed).
1. 99% of the tubes in our department used are economy tubes and they are frequently re-used over and over. They do tend to eventually break or warp as students clean and/or dry them. For the typical sample I think they work perfectly fine over multiple samples.
1. We've gone to the Norell Caps (Sample Vault?), and have been really pleased with them.
They can be reused a few times.
Thanks.
Robin
From: Robin Stein <robin.stein_at_mcgill.ca>
Sent: September 9, 2019 3:42 PM
To: ammrl_at_ammrl.org
Subject: AMMRL: NMR tubes: can economy tubes be reused?
Hi all,
We've had some questions about reusing economy NMR tubes such as Bruker Sample Jet tubes. Has anyone had experience with these tubes in an open-access chemistry environment?
Thanks.
Robin
Robin Stein
MC2 Facility, NMR/EPR
McGill University
Room 35, 801 Sherbrooke St W
Montreal, QC H3A 0B8
https://mcgill.ca/mc2
Received on Sat Sep 21 2019 - 13:40:44 MST