Hi all,
I ran a dosy to calibrate the gradient using sample D2O on a DPX 400 under
XWINNMR 2.6. The data was processed using XWINNMR T1/T2 module. The fitting
curve was great, but the diffusion coefficient measured was much bigger than
that in the literature ( I got 8.67 at 25C, while it is 1.87 in literature).
I don't think the calibration gradient constant caused the huge error,
because its current value is 5.54G/mm, which is in well agreement with our
high resolution Z-gradient probe. I suspect something is wrong with the AU
program dosy, which I used to set up the dosy experiment, but I have no clue
what is wrong.
I just followed the manual "Measure diffusion by nmr (August 2000)" from
Bruker, to set up and process the dosy. I used ledbp2s1d to optimize the
parameters like p16, and then executed AU program "xau dosy" to acquire the
data, in which the pulse sequence is ledbp2s.
Thank you in advance for any input!
Guangyu
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Guangyu Li
NMR Spectroscopist
100 Choppin Hall
Louisiana State University
Baton Rouge, LA 70803
USA
Tel: 225 578 5346
Fax: 225-578-8826
Email: ligy@lsu.edu
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