From: Allen Minton <minton@helix.nih.gov>
  To  : Jeffry C. Nichols <jcn@bioc.rice.edu>
  Date: Fri, 15 May 1998 10:19:32 -0400

Re: high temperature spins

Jeffry C. Nichols wrote:

> I haven't seen this discussed or anything in the literature,
> but has anyone had experience with running either velocity
> or equilibrium scans at high temp (high temp meaning
> somewhere between 50-70 deg C)?

    In principle, high temperature sedimentation equilibrium can be done
using post-centrifugation fractionation of gradients formed in a prep
centrifuge (see Darawshe et al, Analytical Biochem. 209, 130-35; 1993).
The only additional consideration would be to ensure that the sample
tubes are cooled uniformly prior to fractionation to avoid thermal
convection.
    A major practical problem is that as far as I know,
temperature-controlled centrifuges designed for biomedical research only
go up to 40-45 deg C.  I think you would have to find a centrifuge
designed for non-biological chemical and/or polymer applications.  IEC
and Sharples used to make such machines, but that was quite a while ago
(tens of years), and I don't even know if they are still in business.
Another option is the relatively inexpensive Beckman Airfuge (Attri &
Minton, Analytical Biochem. 133, 142-52; 1983).  You achieve temperature
control by heating or cooling the compressed air used to drive the
turbine/rotor.  I think it would work fine at 70 deg.

Allen Minton