Dear Friends
For calibrating the Z-gradient strength in my probes, I use a sample
that basically has a polymer plug matching the U shape of a standard 5
mm NMR tube, that has a cylindrical shell scooped out. I can push this
plug into a 5 mm tube filled with water. Carefully done, the cylindrical
shell is now full of water and the polymer is of such a type that
contains no protons in it. I pipette out any water above the plug so
that the only 1H nuclei are those trapped in this 'cylindrical annulus
shell'.
The height of this 'cylindrical annulus' is precisely machined to be
5 mm. By applying various gradient % values and recording the 'top hat'
like profile from the water, I calculate the Hz per (cm -A), which I
convert to the more useful Gauss/ cm-A .
Thank you for indulging me up to this point of the narrative. Now,
the questions :
* Do you all use a similar setup or anything else to calibrate the
gradients (standard solvent with known D at a given temperature,
etc.) ?
* If it is the former, how reliable is your calibration and more
importantly, how do you cross check this ?
* If it is the latter, can you please share with the community, how
you do it so that mere mortals like me can reverse engineer it at
my end ?
Thank you as always and hope all of you from the Northern hemisphere are
enjoying a wonderful summer unfolding ...
Best Regards
Rajan
--
*_______________________________
Rajan K Paranji, Ph.D.
*NMR Facility Manager
Department of Chemistry
Room 65, Bagley Hall
University of Washington
*Seattle, WA 98195*
*ph: 206 685 2581 pager:206 680 3779
fax: 206 685 8665
email: paranji_at_chem.washington.edu
___________________________________*
Received on Tue Jun 16 2009 - 07:25:43 MST