gel chromatography

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Kutty's picture
gel chromatography

In gel filtration chromatography why the small size particles can not move through way of large particles?

Sami Tuomivaara
Sami Tuomivaara's picture


The relative rate at which particles move through a gel filtration column depends on the relative sizes of the particles. Think of it as a race between small and large particles. At start line (when particles enter the column), small and large particles are side by side... When they start moving through the column along with the flow of the liquid medium, large particles only go some of the larger pores (because they don't fit in the small pores) in the gel and rush through the column rapidly. Smaller particles visit all pores (small and large) in the gel, because they fit in all of them. Small particles hence spend substantial time in going in and out of all of the pores whereas large particles visit only those few that large enough. Since large particles don't spend all that time in side-stepping from the main course (the vast open space between the gel pores), they finish the race faster...

Here's a wikipedia article describing gel filtration chromatography. If you want more advanced text, chromatography textbook from science library would do it...