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<TITLE>Re: [RASMB] sedimentation</TITLE>
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Hi Irene<BR>
<BR>
There is a long history of using the AUC to look at PSL particles, starting (I think) with a lovely paper by Cheng & Schachman (1955) J Polym Sci 16:19+ which established what is still the most precise reference data for validating the application of Stokes Law to small spheres, as well as characterising the s-c dependence of such spheres.<BR>
<BR>
As the density of PSL is quite close to 1, you can get away with looking much larger PSL particles in the AUC than you could with denser (e.g. protein-based) material. As you have the freedom to adjust the density difference and make it even smaller by adding (say) salt or deuterium oxide to the solvent, I doubt that there <U>is</U> any real upper limit to the size of spheres you can cope with, when running the AUC at low speeds.<BR>
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All best wishes for your work<BR>
<BR>
Regards<BR>
<BR>
Arthur<BR>
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Arthur J Rowe<BR>
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<BLOCKQUOTE><B>From: </B>"Irene Hallyburton" <i.hallyburton@dundee.ac.uk><BR>
<B>Organization: </B>Dundee University<BR>
<B>Date: </B>Fri, 24 Oct 2003 12:09:48 GMT<BR>
<B>To: </B>rasmb@rasmb-email.bbri.org<BR>
<B>Subject: </B>Re: [RASMB] sedimentation<BR>
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Hi All<BR>
<BR>
In the same vein as Jan's silica particles, a client has been using latex <BR>
microparticles in the development of Point of Care assays. He has <BR>
asked me about looking at them, coated and uncoated, in the AUC. <BR>
They will be quite large, and we did consider DLS, but our instruments <BR>
max is 50nm and they'll be bigger than that.<BR>
<BR>
What is the upper size range for AUC?<BR>
<BR>
Many Thanks<BR>
<BR>
Irene<BR>
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<0>-<0>-<0>-<0>-<0>-<0>-<0>-<0>-<0>-<0>-<0><BR>
Irene Hallyburton<BR>
Post Genomics & Molecular Interactions Centre<BR>
Faculty of Life Sciences<BR>
University of Dundee<BR>
01382 348700<BR>
<BR>
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