How does G-50 work?

Jim Kami jakami at
Sun Jun 11 15:21:17 EST 2000

    Imagine a road with many, even sized potholes in it. Small tires get
caught in the potholes and have to move slowly to get through. Very large
tires can't enter the potholes. They just roll over them and can move very
    The number after the G in the Sephadex series indicates the pore size,
smaller numbers for smaller pores. The Stokes radius of a molecule
determines which pores it can enter. A molecule with large radius will be
"excluded" from smaller pores, bypass the beads and travel more rapidly
through the column. A molecule with a small radius will be trapped within
the pores and move more slowly through the column.
    hope this helps,

Jim Kami

kab35 at wrote:

> Could you please explain (I must  have a mental block) how G-50 allows
> linearized labeled riboprobe to pass through and how unlabelled
> nucleotides are trapped in the G-50 column?
> I understand size exclusion must play a role,
> Thanks,
> KB
> Sent via
> Before you buy.

More information about the Methods mailing list