Displacement study on a vancomycin-based stationary phase using N-acetyl-D-alanine as a competing agent

Area of Science:

• Chromatographic separation science
• Chiral chemistry
• Analytical chemistry

Background:

• Vancomycin is a macrocyclic antibiotic used as a chiral selector in chromatography.
• Chiral recognition mechanisms are crucial for separating enantiomers.
• Understanding solute-stationary phase interactions is key to optimizing chromatographic methods.

Purpose of the Study:

• To investigate the binding of D,L-dansyl amino acids on a vancomycin stationary phase.
• To analyze the effect of N-acetyl-D-alanine as a competing agent in the mobile phase.
• To model stereoselective and nonstereoselective interactions in chiral separations.

Main Methods:

• High-performance liquid chromatography (HPLC) using a vancomycin stationary phase.
• Elution analysis with and without N-acetyl-D-alanine as a mobile phase additive.
• Development and application of a theoretical model to fit experimental retention data.

Main Results:

• N-acetyl-D-alanine acts as a specific competing agent for the aglycone pocket of vancomycin.
• A theoretical model adequately describes the dependence of solute retention on the competing agent.
• Dansyl amino acids exhibit enantioselective binding to the aglycone pocket of vancomycin.
• Additional enantioselective sites on the vancomycin surface contribute to chiral discrimination.

Conclusions:

• This work represents the first displacement study on a macrocyclic antibiotic stationary phase.
• Dansyl amino acid binding to vancomycin is enantioselective and involves the aglycone pocket.
• Multiple enantioselective sites on the vancomycin surface are involved in chiral discrimination.