Capillary electrophoresis investigation on the structure-enantioselectivity relationship in synthetic cyclopeptides as chiral selectors

We recently reported the use of a deconvolution strategy to identify the be st chiral selectors for N-alpha-2,4-dinitrophenyl (Dnp) amino acid racemate s from a combinatorial library composed of thousands of homodetic cyclohexa peptides. Selection was based on the capillary electrophoresis (CE) enantio resolution for a set of Dnp-amino acids. The groups involved in the chiral discrimination were assessed by nuclear magnetic resonance (NMR) spectrosco py, which revealed a strong involvement of one of the aromatic rings of the cyclopeptide in the binding with the analyte. In order to better understan d the recognition mechanism, and thus extend the applicability of the analy tical system, modifications on both analyte and selector structure were int roduced. The effects on separation were evaluated in terms of resolution va lues and mobility variation.