CHIRAL SEPARATIONS OF ATROPINE AND HOMATROPINE ON AN ALPHA-1-ACID GLYCOPROTEIN-BONDED STATIONARY PHASE

Chiral separations of cationic compounds were studied with two structurally very similar compounds, atropine and homatropine. Retention, resolution and sensitivity were studied by isocratic and gradient elution techniques using changes in pH, temperature and concentrations of 2-propanol and anionic additives. Anions of octanoic acid and 2-phenylbutyric acid improve the chiral separation of atropine whereas the chiral selectivity for homatropine can be suppressed. (R)- and (S)-2-phenylbutyric acid give different separation factors for atropine, which indicates a specific interaction with the solute. The antipodes of the cations are retained by different mechanisms in the presence of anionic additives, as demonstrated by experiments with factorial design, Van 't Hoff plots and the indirect detection technique. © 1990.