My thanks to the (21) people who responded to my request for
request for observations on the use of disposable NMR tubes. I'll try and
summarise the responses here.
- A number of groups are using disposable tubes and running very large
numbers of spectra/year. Most of this group report no more than usual tube
or insert breakages, and are happy customers.
- One reply was from a user who had negative experiences and feels strongly
against disposable tubes.
- Tube breakages during insertion in the magnet appear to be more likely
than insert scoring/breakage.
- It's probably worth reiterating that a high-quality tube dried in a hot
oven is probably rendered poorer quality than a cheap disposable tube.
- A number of people use Wilmad's tube tester (SB-5-7) to select good
tubes. One user rolls the tubes on a flat surface to achieve the same
selection.
- Most agree that shimming is OK for disposable tubes, but larger SSBs and
slower shimming were mentioned.
- One user remarked that hard glass is preferable over Pyrex because
magnetic susceptibility considerations make it easier to shim.
- Some find a happy medium by using disposable tubes for samples that are
difficult to clean, such as gels.
- There was no clear consensus on vendor preference. Some preferred Wilmad
over Norell, and vice versa for others. But these are not the only game in
town. One user is happy with WIZCO (Joe.Zhou@zepmfg.com), another uses
Kimble-Kontes (JuneHoskin@aol.com in Europe), and a third (in Japan) favours
Shigemi.
I hope this helps. We'll get some tubes and do a trial run with a group of
chemists. Again, my thanks to all who responded. Write to me if you want
additional info. I'll do my best, but shan't pass on a name without
consent!
Yours on resonance,
Mike
Michael A. Bernstein
AstraZeneca R&D Charnwood
Bakewell Rd,
Loughborough, Leics.
UK LE11 5RH
Phone: +44 1509 644 140
FAX: +44 1509 645 576
Michael.Bernstein@astrazeneca.com