A family of single-isomer, sulfated gamma-cyclodextrin chiral resolving agents for capillary electrophoresis. 1. Octakis(2,3-diacetyl-6-sulfato)-gamma-cyclodextrin

The first member of the single-isomer, sulfated gamma-cyclodextrin family, the sodium salt of octakis(2,3-diacetyl-6-sulfato)-gamma-cyclodextrin (ODAS -gamma CD) has been synthesized, analytically characterized, and used to se parate, by capillary electrophoresis, a variety of neutral, acidic, basic, and amphoteric enantiomers in low pH background electrolytes. The anionic e ffective mobilities of the neutral and anionic analytes were found to incre ase with the concentration of ODAS-gamma CD. For weakly binding cationic an alytes, the effective mobilities went from cationic high values, through ze ro, to increasingly larger anionic values as the concentration of ODAS-gamm a CD was increased. For the strongly complexing cationic analytes, the effe ctive mobilities became anionic even at very low ODAS-gamma CD concentratio ns and became smaller as the ionic strength of the background electrolyte i ncreased with the increasing ODAS-gamma CD concentration. Separation select ivity followed the predictions of the charged resolving agent migration mod el: for neutral analytes it decreased as the concentration of ODAS-gamma CD was increased. For cationic analytes, selectivities were found to increase as the cationic effective mobilities approached zero, then decreased as th e concentration of ODAS-gamma CD was increased further. The extent of peak resolution that could be realized with ODAS-gamma CD strongly depended on t he magnitude of separation selectivity and the normalized electroosmotic no w mobility. ODAS-gamma D proved to be a broadly applicable chiral resolving agent.