Hi all-
Can anyone give me a good practical explanation of "polydispersity" in size exclusion chromatography? I know it is Mw/Mn, but what does that really mean?
Thanks,
Jeff

Polydispersity is simply a convenient way to characterize the width of the molecular weight distribution of a polymer. Mw is the weight average molecular weight of the polymers in the mixture (this value is biased high since large molecules contribute more to the weight average than small molecules). Mn is the number average molecular weight in the mixture (this value is biased low since small molecules contribute more to the total number of molecules than do large molecules). A perfect distribution would have a value of one. A more detailed explanation can be found at the following: http://www.ampolymer.com/FRD/Question%20of%20Mw.htm

Chris-
Thanks for your response and the link.
-Jeff