Question

2. Some common types of chromatography include adsorption (which is typical in TLC), ion-exchange (where ions are attached to the stationary phase and interact with oppositely-charged ions in the mobile phase), molecular exclusion (where larger molecules are not able to enter the pores in the stationary phase), and affinity (which employs specific interactions between solute in the mobile phase and molecules attached to the stationary phase). Which type of chromatography would be best suited to a separation of the following:

a. …peptides of various sizes?

b. …an antigen known to bond strongly to an antibody?

c. …a mixture of polar and non-polar compounds?

d. …positively-charged amino acids?

Answer 1

A:- (a) peptides of various sizes => molecular exclusion (where larger molecules are not able to enter the pores in the stationary phase)

      (c) a mixture of polar and non-polar compounds => molecular affinity (which employs specific interactions between solute in the mobile phase and molecules attached to the stationary phase)

     (d) positively-charged amino acids => ion-exchange (where ions are attached to the stationary phase and interact with oppositely-charged ions in the mobile phase)