I would like to thank all of those responding to my question about the NMR
sample tubes. Some of you requested that I share the summary of responses.
Best regards,
Jaroslav Zajicek
Assist. Faculty Fellow
Department of Chemistry and Biochemistry
University of Notre Dame
Notre Dame, IN 46556
Phone: (219) 631-9111; Fax: (219) 631-6652
The Summary of Responses
1)
We have had good luck with tubes from NEW ERA ENTERPRISES. Contact
Frank BoscoPO Box 425 Vineland New Jersey 08360-9945, ph. (609)
794-2005, fax (609) 697-8727. Tell him that I sent you (maybe he
will give me an even better deal.)
best of luck
2)
My experience is you get what you pay for.
kkkkT
3)
NEW ERA ENTERPRISES
PO BOX 425, VINELAND NJ 08360-9945
609-794-2005
4)
Jaroslav:
We use the Wilmad Thrift tubes on our 500 here at 3M, but are usually
running polymers which do not show high resolution proton spectra (and which
also are impossible to clean). On rare occasions we are unable to shim
a sample, but 99% of the time we obtain good spectra with proton resolution
under 1 Hz (if the sample is not too viscous or a gel). We have experience
only two broken tubes in the probes over the past 5 years using these cheap
tubes, at a savings in tube costs (since we run 10,000 samples a year) of
over $30,000 per year and a cost of repairing probes of under $2000 per year.
5)
Fisher Scientific sales KNOTE's NMR tube. we use the 240 (highest grade)
on 500 without any problem. Your institute might have contract discont
with Fisher for the NMR tubes. Wilmad's coaxial insert also works in
KONTE's tube.
6)
Jaroslav,
Our stockroom was choosing brands a couple of years ago, so I asked
everyone what they were using. Its probably a little dated, but this
is the summary of those responces:
Thanks to everyone for your tube comments. This has taken me longer to
digest than Thanksgiving dinner but I've learned a lot.......
Most of our magnets have fielded many tube types, but our stockroom's
are supplied by these vendors:
Wilmad 77%
Norell 13%
Kontes 3%
New ERA 7% to the nearest %
one multi-vendor facility was cut in half
Insert scoring was more divisive with 20% believing, 20% disbelieving,
and 20% feeling that hot or long drying in ovens are the root of all
warped tube and insert problems. Wilmad recommends drying on a
perfectly flat tray at 125 deg C for 30 to 45 minutes,,,,,it may get
out of round and not fit in the spinner but not bent and ruin the probe.
The Wilmad concentricity tester (SD-5-7 for $7.00) which is a piece
of precision glass just big enough for a tube to slide through is
recommended as the best way to find tubes to throw out (if you can
convince a graduate student to toss an unbroken tube). Roundness
can also be tested by rotating a tube in a micrometer, with steady
resistance correlating to roundness.
............
comments (by vendor):
Wilmad:
528's ordered over a period of 4 years scoring inserts,
only one spot on the tube showed wear.
507's for everyday,,, 528's for important
507's are not good enough for water suppression.
507's work fine at 500MHz, but more often found at 300.
Do not break when freezing a sample in liquid nitrogen
for sealing, other tubes did.
Thrift tubes work well 99% of the time with no scoring observed.
Never had any problems with (common responce).
528 or better required at 300MHz and above.
528 or better required in all instruments.
Norell:
Spinning sidebands were a problem.
Avoid as much as possible.
Not Pyrex so don't try to seal to pyrex accessories.
Borosilicate glass doesn't warp as easily in a drying oven.
About 5% of the XR-55's give spinning artifacts which look like
coupling, but for $2.00 you can throw these out.
OK for general purpose work at 300MHz
most bang for the buck
508UP used (almost) exclusively
Kontes:
Overrates so you need to buy a better grade
Difficult to shim.
New ERA:
performance comparable to Wilmad for less money.
high quality
good experience.
Corning:
Good luck with (we had)
Throw Aways:
Increased rate of tube breakage in the probe.
............
The insert scoring boogey guy (this can be inclusive in the midwest) may be
disappearing. On a recent demo trip, none of the ap lab spectroscopists
routinely spun their samples. The mapped fields seem to make this
unnecessary,,,, will we still call them spinners?
Hope this has been useful,,,wish the tube vendors were on internet
to see if they agree with all of this,,
hope that this helps,
7)
It really depends on the probe(s). We have Nalorac probes which tend to
hold to very tight tolerances with respect to clearance between the glass
insert and the sample tube itself. Wilmad sells glass cylinders to evaluate
camber of NMR tubes. Before attempting to substitute tubes, I would
suggest acquiring one of these gauges. You get hat you pay for, replacment
glass inserts can cost > $1000.00. We allow the use of 528's only!
Regards,
8)
Dear Jaroslav,
John Bodnar of Wilmad told me that Wilmad 512 tubes which cost
only about 5 cents more than Thrift tubes are actually reject 507-PP and
528-PP tubes. I was looking for tubes which could be sealed off at a
reasonable cost. If you were willing to select tubes, you could probably
do quite well on these, particularly for 2-D experiments where spinning
is not done.
9)
Dear Jaroslav
Mark W. Norell, owner of Norell, Inc., was kind enough to send our NMR
laboratory a nice free assortment of the NMR tubes and solvents that are sold
by his company. Our facility is limited to a 200 MHz instrument. Therefore
I can not give any personal recommendation based upon experience at higher
fields.
The information packet that arrived with the samples has comparitive spectra,
at 500 MHz, between Wilmad 528-PP and Norell XR-55 NMR tubes. Take a look
for yourself. Please let the group know the outcome.
Address:
Norell, Inc.,
120 Marlin Lane,
Mays Landing, NJ, 08330, USA
Telephone: 800-222-0036
Best Regards,