Immobilization of cellulase on monolith supported with Zr(IV)-based metal-organic framework as chiral stationary phase for enantioseparation of five basic drugs in capillary electrochromatography.

Metal-organic framework (UiO-66-NH2)-incorporated organic polymer monolith was prepared by thermal polymerization. By virtue of the superior physical and chemical properties, the UiO-66-NH2-modified organic monolith was then functionalized by chiral selector cellulase via the condensation reaction between the primary amino groups and aldehyde groups. The synthesized materials were characterized by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectrometry, thermogravimetric analysis, and nitrogen sorption isotherm. The cellulase@poly(glycidyl methacrylate-UiO-66-NH2-ethylene glycol dimethacrylate) (cellulase@poly(GMA-UiO-66-NH2-EDMA)) monolith was applied to enantiomerically separate the basic racemic forms of metoprolol, atenolol, esmolol, bisoprolol, and propranolol. In contrast to the cellulase@poly(GMA-co-EDMA) monolith without UiO-66-NH2, the cellulase@poly(GMA-UiO-66-NH2-EDMA) monolith reveals significantly improved enantiodiscrimination performance for metoprolol (Rs: 0 → 1.67), atenolol (Rs: 0 → 1.50), esmolol (Rs: 0 → 1.52), bisoprolol (Rs: 0 → 0.36), and propranolol (Rs: 0 → 0.44). The immobilization pH of cellulase, buffer pH, UiO-66-NH2 concentration, and the proportion of organic modifier were evaluated in detail with enantiomerically separating chiral molecules. The intra-day, inter-day, column-to-column, and inter-batch precision have been discussed, the result was preferable, and the relative standard deviation (RSD) of separation parameters was <4.3%. Schematic representation of the preparation of a UiO-66-NH2-modified organic polymer monolith for enantioseparating five racemic β-blockers. UiO-66-NH2 was synthesized and converted into a monolith as the stationary phase. Then, the modified monolith containing cellulase as the chiral selector was applied in a capillary electrochromatography system for enantioseparating chiral drugs.