Question

A mixture of two amino acids having pl 9.60 and 5.40 can be separated

• A. By adjusting the pH of the solution at 9.60
• B. By adjusting the pH of the solution at 4.20
• C. By adjusting the pH of the solution at 7.0
• D. By adjusting the pH of the solution at 7.5

Answer 1

The correct option is A

By adjusting the pH of the solution at 9.60

Every amino acid exists exclusively as dipolar ion when the pH of the solution is equal to its isoelectric point (pl), hence at this pH it does not migrate to either electrode, while at other pH, an amino acid migrates either to cathode or to anode depending upon its pl. Thus at pH 9.60, amino acid with pl 5.40 will exist as an anion and migrate to anode ; while that with pl 9.60 will not migrate to any electrode.