Below are some posibilities, which are a result of a related problem presented
past february (1998).
When I analyze phospholipids mixture by 31P, I use triphenylphosphine. Using a
solvent ratio 1:3 of Methanol/CDCl3, relative to H3PO4, shows its signal at a
chemical shfit of -5.29 ppm.
Have a nice day,
JOE
Previous survey:
Dear all,
I received many replies to my request for information regarding 13P-NMR
standards. The replies may be summariesed as follows.
The standard for 31P NMR is external 85% H3PO4 in H2O. Beware of bulk
magnetization effects. Concentration affects the chemical shift so if you
want accuracies better than +/- 0.05 ppm, check the concetration by titration.
Two secondary references were suggested: eternal hexamethylphospharimid
in H2O (30.73 ppm) and internal dilute trimethyl phosphate (3.09 ppm CDCl3,
3.78 ppm D2O, 3.49 ppm CD3OD, 3.95 ppm acetone-d6).
I hope that these results are of help.
Yours,
Roy.
--------------------------------------------------------------------------------
V Dr. Roy Hoffman,
I Manager, NMR Laboratory, Department of Organic Chemistry,
A a X The Hebrew University of Jerusalem, Jerusalem, Israel 91904.
XJ lX Tel. (972) 2 6585327, Fax (972) 2 6585345, Email roy@shum.cc.huji.ac.il
X X Web page http://drx.ch.huji.ac.il:8080/hoffman.html
X
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Edward T. Chainani wrote:
> ammrl'ers,
>
> does anybody know of a reference compound for 31P NMR that doesn't crowd
> in with the other peaks in biological systems? The typical reference
> compound, 85% phosphoric acid, has a peak in the middle of the chemical
> shift range of interest.
>
> I've encountered methylenediphosphonic acid (CH6O6P2) in the literature
> (Magnetic Resonance in Medicine 33:795-800; 1995). Has anyone ever used
> this? I hope someone can tell me the chemical shift with respect to
> phosphoric acid.
>
> ------------------------------------------------------------------------------
> Edward T. Chainani Nuclear Magnetic Resonance Laboratory Manager
>
> National Chemistry Instrumentation Center (NCIC)
>
> Ateneo de Manila University phone: (632) 426-6001 loc. 2309
> Loyola Heights, Quezon City e-mail: etch@ginto.chem.admu.edu.ph
> Philippines FAX: (632) 426-5985
> ------------------------------------------------------------------------------
-- ____________________________________________________________JOSE R. MARTINEZ ORTIZ Tel. (787)764-0000 x4819 UNIVERSITY OF PUERTO RICO joenmr@uprnmr1.chem.uprr.pr DEPT. OF CHEMISTRY joenmr@worldnet.att.net PO Box 21352 UPR Station joenmr@latino.com San Juan PR 00931-1352 http://home.att.net/~joenmr/ http://uprnmr1.chem.uprr.pr ____________________________________________________________