A protein-based mixed selector chiral monolithic stationary phase in capillary electrochromatography†
A new mixed selector chiral stationary phase (CSP) was prepared with co-immobilized human serum albumin and cellulase on a poly(glycidylmethacrylate-co-ethylene glycol dimethacrylate) (poly(GMA-co-EDMA)) monolith and the evaluation of its usefulness in chiral separation research was presented. For comparison, two single selector chiral stationary phases (CSPs) were also fabricated with the corresponding proteins. The enantioseparation ability of these CSPs was investigated by capillary electrochromatography (CEC) with various racemates. The mixed selector CSP exhibited a broader range of enantioselectivities than the single selectors and it could separate 10 chiral analytes while the two single selector CSPs resolved 3 and 8 respectively. Moreover, for (±)-warfarin, the enantioresolution was improved on the mixed selector CSP. Meanwhile, compared with the single selector CSPs, no additional preparation stage or reagent consumption was required in the simultaneous immobilization of different proteins, which is more favorable from economical and practical points of view. Consequently, by mixing HSA and cellulase together, the composite column combines the enantioselectivities of both individual proteins, thus expanding their application range practically.