Dear ammrlers,
We're trying to decide which experiments would be most revealing
and useful in pre-purchase demos of instruments with field
strengths >= 700 MHz. The proposed purchase is for an 800 with
cryoprobe that will be dedicated to biomolecular work. I would
deeply appreciate advice from you on the following questions
(answers will be held in confidence unless you explicitly state
otherwise):
Are there characteristics of high-field instruments that should cause
us to place a different weight on each of the "standard acceptance
tests"
than would be the case for a lower field instruments? If so, which of
these tests are most important?
Are there experiments that you would recommend that could help us decide
how well the instrument will perform on "real" samples? We are
particularly
concerned about the performance of a cryoprobe on samples with high
ionic
strength (up to 2M).
There is a rumor that shielded 800 magnets drift rapidly. Is this true?
For either a shielded or unshielded magnet, should we spend any of our
short demo time on evaluating drift and/or the stability of homogeneity?
Are there any reasons that cryoprobe results gathered at 600 MHz cannot
be "scaled" to project performance at 800 MHz?
Are there any of the common protein-structure sequences that are
particularly difficult to run on either vendor's high-field machines?
Any other comments or suggestions?
Thanks in advance,
Bill Kearney
Wm. R. Kearney, Ph.D.
Director
College of Medicine NMR Facility
58 EMRB
The University of Iowa
Iowa City, IA 52242
ph. (319) 335-6610
fax (319) 335-8049
william-kearney_at_uiowa.edu
Received on Thu Jun 19 2003 - 12:21:23 MST