| Optimum Rf (reference) | Simulation Rf |
|---|---|
| Aspartic acid : 0.28 | Aspartic acid : |
| Lysine : 0.15 | Lysine : |
| Leucine : 0.74 | Leucine : |
Amino acids exhibit different Rf values depending upon the pH of the solvent system. Acidic amino acids (Aspartic acid) shows increase in Rf values with increase acidic nature of the solvent system. Basic amino acids (Lysine) shows decrease in Rf values with increase in acidic nature of the solvent system. However, no mark effect is observed in neutral amino acid (Leucine). The reverse effects in terms of Rf value are obtained with basic nature of solvent system as expected.
The polarity of a solvent system to be used for chromatography is evaluated by examining the dielectric constant and dipole moment of the solvent. The larger these two numbers, the more polar is the solvent. In addition, the hydrogen bonding ability of the solvent is also considered.