a) A student performed chromatography of the four amino acids and the results were shown in the chromatogram. If an anion exchange column (column is positively charged) was used in a neutral buffer, assign each amino acid to the corresponding peak in the chromatogram.
b) Write 2 – 3 sentences to describe the interactions that will occur for each amino acid with the anion exchange column and its effect on column retention.
c) Write 2 – 3 sentences to describe how the results would differ if a cation exchange column (negatively charged column) were used.
a) Peak 1: Lysine; Peak 2: Arginine; Peak 3: Glutamic Acid; Peak 4: Aspartic Acid
b) Lysine will interact with the positively charged anion exchange column through electrostatic attraction, resulting in a longer retention time. Arginine will interact with the column through hydrogen bonding, resulting in a shorter retention time. Glutamic acid will interact with the column through electrostatic attraction, resulting in a longer retention time. Aspartic acid will interact with the column through hydrogen bonding, resulting in a shorter retention time.
c) If a cation exchange column (negatively charged column) were used, Lysine and Glutamic acid would interact with the column through electrostatic repulsion, resulting in a shorter retention time. Arginine and Aspartic acid would interact with the column through hydrogen bonding, resulting in a longer retention time.