Re: nmr sample volume

Shaoxiong Wu (swu@learnlink.emory.edu)
Thu, 05 Nov 1998 15:08:22 -0500

There is a cost fact by standarizing sample tube, volume etc. If you need
a good spectrum
good solvent (>99.9%D, 25% more $), a good tube 528pp ($8.85each) or 535pp
($12 each) are necessary.
If just get a spectrum (most organics do), they could use cheap tube, and
cheap solvent, save $$$ (Most students
do not care much about that, but you do).
We stock 507pp ($5.35) for all, they can buy good one as they need it.
Sample volume is limited to 0.4ml -0.75ml. Out of the rang is their
problem since
they have to spend more time to shim on it. Our standard is 0.6ml (depends
on the coil length of your probe.
Good Luck on your standarization.

Some of you may know the cheapest 5mm tube on the market is $0.75 each. I
have tested it. Good
enough for "dirty job" on 300MHz.

Shaoxiong Wu, Ph.D.
Director, NMR Research Center
Emory University
404-727-6621

sur@chem.rochester.edu writes:
>Dear AMMRL members:
>
>I have been thinking to standarize sample volume/height and tube quality
>for routine and not-so-experienced nmr users in our department. I am sure
>these and similar nmr management issues were discussed before, but I want
>to receive some feedback from your own experiences.
> It is difficult to judge the quality of each nmr tube by routine
>student users, and I recommend using at least Wilmad 528-pp at 400 MHz or
>even at 300 MHz. The sample height for high resolution nmr in a 5 mm tube
>should be about 5 cm high. I have seen recommendation of 4 cm sample
>height, too. For expensive solvents, smaller sample height is, however,
>desirable.
>
>Thanks in advance for your comments,
>
>Sandip