This may sound silly, but what do you do to ensure that the 5 mm NMR
tubes from Wilmad are clean? I mean, are you supposed to assume that
they come from the factory clean? We still wash them in an ultrasonic
cleaner with a water/"Teepol" detergent solution, and then dry them with
reagent grade acetone, followed by a blast of nitrogen gas. I feel
(actually, my colleagues who do the procedure strongly feel) that this is
an unecessarily tedious procedure. Any suggestions?
Thanks in advance.
------------------------------------------------------------------------------
Edward T. Chainani e-mail: etch@admu.edu.ph
National Chemistry Instrumentation Center Phone: (632)924-4601 loc 2309
Ateneo de Manila University
Loyola Heights, Quezon City
Philippines
------------------------------------------------------------------------------
**
Dear Edward,
I don't think you can assume that they are clean on arrival, I certainly
remember one that wasn't (I was rushing and used it 'raw' and It changed the
colour of a solution!). Your procedure seems reasonable, I'm afraid to say.
Your colleagues will have to make the effort.
Graham
--/ Dr. Graham Barlow, NMR Service Manager \ / gkb1@york.ac.uk \ [ Dept. of Chemistry, Univ. of York, York, UK ][ Tel: 01904 432506 ] [ http://www.york.ac.uk/depts/chem/nmr ][ Mobile: 0402 181253 ] \ http://www.york.ac.uk/~gkb1/ / \ Fax: 01904 432516 /
**
Wilmad tubes from the factory are NOT clean. The above is the way we clean our tubes too, and we do so with new tubes as well. Your colleagues may get away with just an acetone rinse and blow dry, but don't let them complain if it dosn't work.
Regards, Andy ============================================================ Dr. A.J.Rous Phone +353-1-7062442 Chemistry Department, 7062133 University College, Fax +353-1-2837873 Belfield, Dublin 4, E-mail andy@fiachra.ucd.ie Irish Republic URL http://fiachra.ucd.ie/~andy/ ============================================================
**
From: rwd@interaccess.com
I guess that depends on what evidence you have, or why you feel they are unclean.
I've been using them right out of the box for high sensitivity 500 MHz proton work
without any objections.
Good luck!
Rick Wintermute Dexter Corp. **
From: Angel C. de Dios<angel@sigma.chem.uic.edu>
Edward, they are clean.
**
From: Mike Meadows<mmeadows@eastman.com>
We use several thousand Wilmad 5mm tubes per year for high resolution proton work. We use the tubes as received and have had no problems with contamination. I would have some concern that sonication might scratch the tubes, but I have never tried that and so don't know.
Best Wishes,
Mike ======================================================================== Michael D. Meadows Principal Research Chemist Eastman Chemical Company PO Box 1972 Kingsport TN 37662-5150 phone 423-229-8826 E-mail mmeadows@eastman.com ========================================================================
**
Edward,
As for your question on wilmad tubes, we do not do anything to the tubes upon receipt from Wilmad. They are clean enough as received to be used directly. You may be expending unnecessary time and resources in this tube cleaning procedure you use. Also, sonication of the tubes may actually damage the tubes by scratching them, thus possibly (with very low probability) damaging the probe insert. Also, if you dry the tubes after this cleaning process in an oven, the possibility of bending the tubes exists with detrimental effects to your probe again. Also, we do not reclaim the used NMR tubes. We just discard the tubes after each use because of the difficulty of getting viscous polymer solutions cleaned out to the tubes. It is cheaper to discard the tubes after one use than it is to try and clean the tubes and risk cross contamination of future samples from poorly cleaned nmr tubes.
Hope these comments help.
Doug
############################################################### Douglas W. Lowman Research Associate Eastman Chemical Company Research Laboratories Eastman Street P. O. Box 1972 Kingsport, TN 37662-5150 Telephone: (423) 229-4728 FAX: (423) 229-4558 Internet: dwlowman@eastman.com ###############################################################
**
Edward,
Your question is not silly! The tubes are clean or not depending on the type of NMR you're going to do in them. For just quick 1d, they probably do not need cleaning (we do not clean ours for cursory inspections. For a careful NOESY or relaxation study you are not doing enough (we soak them in hot acid over night) to make sure to remove all metal ions. If you want the more elaborate procedure, I can send.
---------------------------------------------------------- Charlie Fry Tel: (608)262-3182 Director, MR Facility Fax: (608)262-0381 Chem. Dept., Univ. Wisconsin Madison, WI 53706 USA email: fry@chem.wisc.edu ----------------------------------------------------------
** From: swolk@ctrqmai.crtq.com
I never wash new Wilmad tubes, and have never seen evidence of significant levels of impurities, even when I've only had micrograms of sample. In all likelihood, your washing procedures will introduce as many impurities as they will remove. But al least with your method, you'll have a good idea what they are. I'd be interested to hear the other responses that you get. Will you post a summary?
**
> >This may sound silly, but what do you do to ensure that the 5 mm NMR >tubes from Wilmad are clean? I mean, are you supposed to assume that >they come from the factory clean?
NO!
>We still wash them in an ultrasonic >cleaner with a water/"Teepol" detergent solution, and then dry them with >reagent grade acetone, followed by a blast of nitrogen gas. I feel >(actually, my colleagues who do the procedure strongly feel) that this is >an unecessarily tedious procedure. Any suggestions?
Depends on what's been in the tube. I soak new tubes in aqueous EDTA. My rinsing procedure is a cycle of water/alcohol/acetone/alcohol/water ending up on acetone prior to drying, for which I prefer an oven.
Do your initial cleaning with a solvent similar to the solvent used in the last sample so that the same things will be solubilized and carried away.
And never use chromic acid!
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ William C. Stevens, Ph.D. Nuclear Magnetic Resonance Facility Director Southern Illinois University Carbondale, IL 62901-4405 wstevens@siu.edu http://www.siu.edu/departments/shops/bill.html wstevens@intrnet.net voice: 618-453-6498 fax: -6408 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
**
Years ago I asked Paul Cope this question, and his answer was that Wilmad's final step was to rinse the tubes in New Jersey water. He left it to me to decide if that was "clean enough".
KAren Ann
Karen Ann Smith karenann@unm.edu Manager, NMR Facility Adj. Asst. Prof. Dept. of Chemistry Clark Hall University of New Mexico Albuquerque, NM 87131 505.277.4031 url: http://www.unm.edu/~karenann "Facts are the enemy of Truth" - Don Quixote
**
NMR samples today are often quite precious, particularly biological samples. Wilmad NMR Sample tubes are cleaned much the way we clean our dishes and glasses before we ship them to you, but they don't meet what chemists like to call "analytical" standards of cleanliness.
Wilmad has a technical bulletin covering the cleaning of NMR Sample Tubes. It can be found on our new Home Page at www.wilmad.com. Select 'Products and Services,' scroll to the bottom of the page and select 'Technical Bulletins.' NMR-010 describes cleaning methods for NMR tubes. It draws attention to a number of 'mistakes' made when cleaning NMR tubes that can affect your results and (tsk, tsk) your hardware.
I hope this helps meet your needs.
Regards:
Paul Cope Market Manager, NMR & EPR Products Wilmad Glass Route 40 and Oak Road Buena, NJ 08310 USA US Tel 1-800-220-5171 x627 US FAX 1-800-220-1081 Int'l Tel ++1-609-697-3000 x 627 Int'l FAX ++1-609-697-0536
Visit our Home Page at www.wilmad.com
**
>From Jerry_Dallas@berlex.com Thu Apr 11 06:26:12 1996
Your diligence is commendable. I have never worried about potential problems but you may be correct. Using acetone as a rinse will likely leave a residue. I would urge you to consider methanol instead. Just avoid heat. regards, Jerry Dallas Berlex Biosciences
**
From: Paul Cope <magrestech@wilmad.com>
Wilmad is proud to announce it's Home Page on the Internet.
Where, you ask? www.wilmad.com of course!
We've also made our 1996 NMR catalog available on the Internet in the Products and Services section. The print version will not be available until June or July. So we'd like you to see if the Online NMR Catalog meets your needs. It's up-to-date, can't be borrowed by your colleagues, and can be accessed anytime of the day or night, things your catalog often isn't. If it meets your needs for our product information, let us know and we'll save another tree!
Also, you can find our technical bulletins online. Scroll to the bottom of the Products and Services page and select Resonance Reports. You can use these with students or non-NMR savvy colleagues, who need a little guidances in NMR-related topics. Great bookmark!
We're new to the Internet, unlike many in the NMR community. We've tried to make our Home Page a valuable tool for you. So let us know how we're doing and what you'd like to see on our Home Page and Online NMR Catalog to make them better for you. Just forward your comments to me or the marketing department E-Mail address that appears at the bottom of many of our pages. And thanks for taking the time to visit us on The Net. We hope you'll stop by often.
Regards:
Paul Cope Market Manager, NMR & EPR Products Wilmad Glass Route 40 and Oak Road Buena, NJ 08310 USA US Tel 1-800-220-5171 x627 US FAX 1-800-220-1081 Int'l Tel ++1-609-697-3000 x 627 Int'l FAX ++1-609-697-0536
Visit our Home Page at www.wilmad.com
**
------------------------------------------------------------------------------ Edward T. Chainani e-mail: etch@admu.edu.ph National Chemistry Instrumentation Center Phone: (632)924-4601 loc 2309 Ateneo de Manila University Loyola Heights, Quezon City Philippines ------------------------------------------------------------------------------