Dear AMMRL,
I have a question that I would like to pass by you. We occasionally
undertake diffusion studies of both small and relatively large
biological and synthetic molecules and assemblies. The larger the
molecules or structures the less diffusion obviously and the easier it
seems to be to get good measurements with larger linear field gradients.
I think larger gradients basically provide a finer meshes or resolution
to discriminate between smaller differences among larger things say
aggregation states at the higher molecular weight ranges. Am I mistaken
here?
We currently have 20 Amp gradient amplifiers that produce linear
gradients fields of about 70 to 75 Gauss//cm depending on the probe. We
are considering new equipment with smaller gradient capabilities at
about 55 Gauss/cm using a 10 Amp gradient amplifier. Do anyone out there
have a feel for doing diffusion studies at 55 Gauss/cm max? Is it enough
for very large molecules and up to what sizes and differences would it
be effective to measure and discriminate between self diffusion
constants? I would appreciate your comments.
--
Francis Picart
NMR Coordinator
Stony Brook University
Department of Chemistry
Room 507
100 John S. Toll Road
Stony Brook, New York 11794-3400
(631)632-7991 Office
(631)632-7960 Fax
Received on Thu May 12 2011 - 09:18:00 MST