IMPROVED CHIRAL STATIONARY-PHASE FOR BETA-BLOCKER ENANTIOSEPARATIONS

The previously described alpha-Burke 1 chiral stationary phase (CSP) w as designed for the chromatographic separation of the enantiomers of b eta-blockers. Difficulties with the reproducibility of the free radica l addition reaction, used in the attachment of the chiral selector to the chromatographic support, have required the development of an alter native silane immobilization process (alpha-Burke 2 CSP). While the en antioselectivity afforded by this new CSP is generally equivalent to t hat of the original CSP, the alpha-Burke 2 CSP demonstrates longer ana lyte retention, necessitating the use of mobile phases of greater eluo tropic strength. The increased retention of the new CSP presumably res ults from a greater surface density of functional selectors, an interp retation which is supported by the observation that the preparative ca pacity of the alpha-Burke 2 CSP is greater than that of the original, Some of the factors influencing the retention and separation of a grou p of 23 beta-blockers on the alpha-Burke 2 CSP are discussed.