Ion-exchange chromatography is a type of chromatography that separates substances based on their electrical charge.
How It Works:
- The column or resin (stationary phase) has charged groups: either positive or negative.
- The mixture containing charged molecules (ions) is passed through the column.
- Molecules with the opposite charge to the resin are attracted and stick to the column.
- Molecules with the same charge as the resin are not attracted and flow through quickly.
- The stuck molecules are later eluted (washed out) by changing the salt concentration or pH of the solution.
Key Idea:
- Separation depends on the strength of the electrical attraction between the molecules and the resin.
- Strongly charged molecules stick longer; weakly charged molecules come out sooner.
Uses of Ion-Exchange Chromatography:
- Purifying proteins, enzymes, and amino acids.
- Removing ions from water in water treatment.
- Separating biological molecules in research labs.
In Short:
Ion-exchange chromatography separates substances based on charge:
- Oppositely charged molecules stick to the column.
- Similarly charged molecules pass through.
- Changing conditions releases the bound molecules for collection.