Imre Toeroe
Wed, 03 Feb 2010 02:37:34 -0800
Hi, this might be relevant here: http://scripts.iucr.org/cgi-bin/paper?S0907444995000436 Imre Clemens Grimm wrote:
regardless of what such a (kinetic) calculator will calculate at the end - we will have to feed it with data of the type "vapour pressure vs. concentration and temperature" of substance X. Even without a whole simulation tool for the kinetics of a vapour diffusion experiment this will already enable us to tell what the equilibrium state/endpoint of the experiment will be. As the substances we are interested in are typically stuff like PEGs and at very high concentration (non-ideal behaviour!), we will need experimental data. For some salts there are tables. But for PEGs etc. this has to be generated. I feel that only having this kind of data at hand would already be tremendously useful!Clemens Zitat von Jacob Keller <j-kell...@md.northwestern.edu>: Dear Crystallographers,Is anybody aware of a calculator for vapor diffusion experiments to plot concentrations of various solvent components as a function of time? For a simple example, what happens when I mix a protein solution containing 50mM NaCl 1:1 with a reservoir containing 50% MPD but no salt? Where is the vapor diffusion equilibrium, and how does the drop composition change as a function of time? More complicated would be experiments involving volatile components other than water, as I think, for example, ethanol would almost instantly equilibrate, then the water diffusion would kick in over a longer time scale. Even more complicated would be pH-dependent volatilities such as acetate. I don't think this would be impossible to figure out, but it would be nice if there were a pre-existing tool/server to do such.Regards, Jacob Keller ******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program Dallos Laboratory F. Searle 1-240 2240 Campus Drive Evanston IL 60208 lab: 847.491.2438 cel: 773.608.9185 email: j-kell...@northwestern.edu ******************************************* -------------------------------------------------- Dr. Clemens Grimm Institut für Biochemie Biozentrum der Universität Würzburg Am Hubland D-97074 Würzburg Germany e-mail: clemens.gr...@biozentrum.uni-wuerzburg.de phone : +49 0931 888 84031 -------------------------------------------------