A reversible gel for chiral separations.
The use of a guanosine gel as a chiral selector in capillary electrophoresis is introduced. Guanosine gels are reversible organized media that are formed through the self-association of guanosine compounds. Their degree of organization and their physicochemical properties can be modulated through variations in guanosine monomer concentration, pH, temperature, and cation content. Baseline resolution of the d and l enantiomers of propranolol was achieved using a reversible biogel formed by 5'-guanosine monophosphate as the run buffer in capillary electrophoresis. Conditions were optimized to provide enantiomeric resolution of 2.1-2.3 in less than 5 min. The reversibility of the gel network offers potential advantages for chiral separations, including the possibility of using thermal or chemical dissociation of the gel network to remove the nucleoside monomers from the separated enantiomers, thereby eliminating the chiral selector as a source of physical contamination of the enantiomerically pure products and spectral background in UV absorbance detection.