Separating complex mixtures

[johnson3AF]

How can you best separate a complex mixture, which exhibits a broad polydispersity on SEC-MALS, that is not sufficiently separated using two or three columns covering a wide range of molecular weight?

[DanSome]

In the case that you cannot find SEC columns which separate your sample, there is another fractionation technique called Field-Flow Fractionation (FFF), which may solve your problem. This technique separates the sample with differential flow velocities; there is no stationary phase, which means that interactions with the stationary phase due to charge or hydrophobic interactions are no longer a concern. FFF fractionates samples across a much larger size range than columns are capable of handling, from 1 nm to 10,000 nm.

[answer provided by Mark Spears, Ph.D., Fujifilm Diosynth Biotechnologies]