Monolithic silica capillary column with coated cellulose tris(3,5‐dimethylphenylcarbamate) for capillary electrochromatographic separation of enantiomers

Abstract

Monolithic silica capillary columns were prepared by a sol-gel process in fused-silica capillaries with an inner diameter of 50 microm and were modified by coating of cellulose tris(3,5-dimethylphenylcarbamate). Influences of the factors in the modification process on enantiomer separations were investigated. The prepared columns were used to perform enantiomer separations by CEC. Fifteen and two pairs of enantiomers were separated under aqueous and nonaqueous mobile phases, respectively, and most of them were baseline-separated with very high column efficiencies. The Van Deemter curve was found flat under high linear velocity of the mobile phase, which indicated favorable kinetic properties of the prepared columns. Baseline separation of a pair of enantiomers was achieved in 90 s with high-column efficiency by short-end separation under high voltage.

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

“…The result of baseline separation of benzoin demonstrated that the chiral selector of CDMPC was well coated onto the hybrid monolith matrices. Compared to the reported data on the CDMPC coated onto pure silica monolith [25] or organic monolith [30], the resolution and efficiency on this hybrid monolith was remarkably lower. The same result was also observed for enantioseparation of benzoin with CLC, as shown in Fig.…”

“…The CDMPC has been successfully coated on either native silica monolith [25] or hybrid monolith synthesized with MTMS/TMOS [37] for chiral separation. Herein, CP-silica monolith would be similarly coated with chiral selectors after straightforward modification with nucleophiles such as ethylene diamine or DETA to form NH 2 functionalities via the nucleophilic substitution reaction, which generates the stronger EOF for CEC.…”

“…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.…”

Integration of Biomolecules into analytical Systems by Means of Silica Sol-Gel Technology

“…86 Baseline separation of a pair of enantiomers was achieved in 90 s with high column efficiency by short-end separation under high voltage.…”

Recent accomplishments in the field of enantiomer separation by CEC

“…Very recently, the group of Zou adapted a procedure earlier proposed by Chankvetadze and co-workers for the preparation of silica monolith-based capillary columns that were modified with cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) as SO for electrochromatographic enantiomer separations of 15 neutral and basic compounds [88]. Thus, first the sol-gel-derived silica monolith was flushed with an acidic solution which should assure rehydroxylation of the silica and ascertain a reasonable silanol density because of its importance as EOF source.…”