Chapter 21.5, Problem 18P

(a)

Interpretation Introduction

Interpretation:

The order of elution of aspartate before serine by $\text{pH-4}$ buffer through a column packed Dowex-$\text{50}$ should be explained.

Concept introduction:

Ion-exchange chromatography is used to separate mixture of amino acids on the basis of their overall charge by using cation or anion-exchange resins.

Dowex-50 is a cation-exchange resins with less polar used for Cation-exchange chromatography.

Cation-exchange chromatography separate amino acids according to their $pI$ values, the lesser the $pI$-value of an amino acid as compared to given pH have the high concentration of negative charged ions. The negative charged ions elute (release from chromatogram) easily from the Cation-exchange chromatogram. And if the amino acids are more polar, then it will also elute (release from chromatogram) easily by the non-polar resins (Dowex-50).

(b)

Interpretation Introduction

Interpretation:

The order of elution of serine before alanine by $\text{pH-4}$ buffer through a column packed Dowex-$\text{50}$ should be explained.

Concept introduction:

Ion-exchange chromatography is used to separate mixture of amino acids on the basis of their overall charge by using cation or anion-exchange resins.

Dowex-50 is a cation-exchange resins with less polar used for Cation-exchange chromatography.

Cation-exchange chromatography separate amino acids according to their $pI$ values and polarities, the lesser the $pI$-value of an amino acid as compared to given pH have the high concentration of negative charged ions. The negative charged ions elute (release from chromatogram) easily from the Cation-exchange chromatogram. And if an amino acid is more polar, then it will also elute (release from chromatogram) easily by the non-polar resins (Dowex-50).

(c)

Interpretation Introduction

Interpretation:

The order of elution of valine before leucine by $\text{pH-4}$ buffer through a column packed Dowex-$\text{50}$ should be explained.

Concept introduction:

Ion-exchange chromatography is used to separate mixture of amino acids on the basis of their overall charge by using cation or anion-exchange resins.

Dowex-50 is a cation-exchange resins with less polar used for Cation-exchange chromatography.

Cation-exchange chromatography separate amino acids according to their $pI$ values and polarities, the lesser the $pI$-value of an amino acid as compared to given pH have the high concentration of negative charged ions. The negative charged ions elute (release from chromatogram) easily from the Cation-exchange chromatogram. And if an amino acid is more polar, then it will also elute (release from chromatogram) easily by the non-polar resins (Dowex-50).

(d)

Interpretation Introduction

Interpretation:

The order of elution of tyrosine before phenylalanine by $\text{pH-4}$ buffer through a column packed Dowex-$\text{50}$ should be explained.

Concept introduction:

Ion-exchange chromatography is used to separate mixture of amino acids on the basis of their overall charge by using cation or anion-exchange resins.

Dowex-50 is a cation-exchange resins with less polar used for Cation-exchange chromatography.

Cation-exchange chromatography separate amino acids according to their $pI$ values and polarities, the lesser the $pI$-value of an amino acid as compared to given pH have the high concentration of negative charged ions. The negative charged ions elute (release from chromatogram) easily from the Cation-exchange chromatogram. And if an amino acid is more polar, then it will also elute (release from chromatogram) easily by the non-polar resins (Dowex-50).