Question

In Gel permeation chromatography or GPC, will small molecules come out of the column slower or faster then big molecules? Why?

Answer 1

Ans:

1.In Gel permeation chromatography very small molecules that are smaller than the pores (in the beads of the stationary phase) enter the pores easily.  As a result, small polymer coils that can enter many pores in the beads take a long time to pass through the column and therefore exit the column slowly.

2.And even if the small moelcules that doesn't enter the pores, they have to move a longer path so they move down slowly compared to the larger molecules.

3.But larger molecules which cannot enter the pores move down the column faster and they need to move only a shorter path as they are large enough.

4.Hence small molecules move down the column slower than the big moelcules in Gel permeation chromatography.