Monolithic silica capillary columns with immobilized cellulose tris(3,5‐dimethylphenylcarbamate) for enantiomer separations in CEC

Abstract

Two types of monolithic silica capillary columns with an immobilized cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) selector were prepared for enantiomer separations in CEC. The monolithic columns were prepared by a sol-gel process in fused-silica capillaries. CDMPC was then either immobilized on a silica monolith through an intermolecular polycondensation of the cellulose derivative containing a triethoxysilyl group, or on a vinylized silica monolith through radical copolymerization of the cellulose derivative, which also contained a vinyl group. IR spectra confirmed the successful immobilization of CDMPC on both columns. Eleven chiral compounds were used to evaluate the enantioselectivity on both column types. Results indicated that the columns obtained via polycondensation had higher separation ability than those obtained via radical polymerization, and that they showed satisfactory run-to-run repeatability and stability. These new techniques thus provide strategies for preparing immobilized polysaccharide-based chiral silica monolithic capillary columns for chiral separations by means of CEC.

Hybrid monolithic columns coated with cellulose tris(3,5-dimethylphenyl-carbamate) for enantioseparations in capillary electrochromatography and capillary liquid chromatography

“…Several kinds of polysaccharide derivatives such as cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC), cellulose tris(4-methylbenzoate), cellulose tris(3,5-dichlorophenyl carbamate) and amylose tris(3,5-dimethylphenylcarbamate) have been coated or immobilized onto the silica-based monoliths and successfully applied for enantioseparations in CLC or CEC [25,26,27,28,29]. However, the drawbacks of silica-based stationary phases are also well known, including a limited pH range of 2-8 in mobile phases due to unstable nature of Si O Si bond in acidic and basic solutions.…”

Enantiomers separation by capillary electrochromatography using polysaccharide‐based stationary phases

“…Another strategy has been to immobilize polysaccharide derivatives onto silica monolithic capillary columns via covalent bonding modification or intermolecular polycondensation . Zou and co‐workers, in order to synthesize a covalently bonded cellulose tris(3,5‐dimethylphenylcarbamate) monolithic silica capillary column, employed the reaction between hydroxyl moieties of cellulose bis(3,5‐dimethylphenylcarbamate) and epoxy groups of 3‐glycidoxypropyltrimethoxysilane‐modified silica monolith .…”

“…The intermolecular polycondensation reaction is an alternative method to prepare immobilized CDMPC or ADMPC monolithic silica capillary columns. In the most recent work, based on the methods previously reported for CDMPC‐based CSP , the immobilized ADMPC onto monolithic silica was achieved by the previous synthesis of amylase (3,5‐dimethylphenylcarbamate) containing triethoxysilyl groups and afterward in situ immobilization onto the monolithic silica matrix in two steps: coating and immobilization via chlorotrimethylsilane in polycondensation conditions. When the concentration of coated amylose derivate was set at 60 mg/mL, 12 out of 15 test racemic compounds (including acidic, basic, and neutral species) were partially or baseline resolved.…”

Enantioselective capillary electrochromatography: Recent developments and new trends

“…Cellulose tris(3,5-dimethylphenylcarbamate) was immobilized through an intermolecular polycondensation or a radical copolymerization approach [53]. For the polycondensation reaction, cellulose tris(3,5-dimethylphenylcarbamate) with a triethoxysilyl group was synthesized and first coated onto a silica monolith.…”