Liquid chromatographic direct resolution of tocainide and its analogs on a (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6-based chiral stationary phase containing residual silanol protecting n-octyl groups

Optically active (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6-based chiral stationary phase (CSP) containing residual silanol protecting n-octyl groups on silica surface was applied to the liquid chromatographic direct resolution of tocainide and its analogs. The chiral recognition ability of the CSP was excellent, the separation (alpha) and the resolution factors (R(S)) for 15 analytes including tocainide being in the range of 3.02-22.92 and 3.94-20.41, respectively. In addition, the chiral recognition ability of the CSP was much greater than that of (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6-based CSP containing residual silanol groups on the silica surface. The chromatographic behaviors for the resolution of tocainide and its analogs were found to be dependent on the content and the type of organic and acidic modifiers and the ammonium acetate concentration in aqueous mobile phase.