Sol‐gel technique for the preparation of β‐cyclodextrin gold nanoparticles as chiral stationary phase in open‐tubular capillary electrochromatography

Abstract

A novel open‐tubular capillary electrochromatography column coated with β‐cyclodextrin was prepared using the sol‐gel technique. In the sol‐gel approach, owing to the three‐dimensional network of sol‐gel and the strong chemical bond between the stationary phase and the surface of capillary columns, good chromatographic characteristics and unique selectivity in separating enantiomers were shown. The influences of capillary inner diameter, coating time, organic modifier, buffer pH, and buffer concentration on separation were investigated. The sol‐gel‐coated β‐cyclodextrin column has shown improved enantioseparation efficiency of chlorphenamine, brompheniramine, pheniramine, zopiclone in comparison with the sol‐gel matrix capillary column. The migration time relative standard deviation of the separation of the enantiomers was less than 0.89% over five runs and 2.9% from column to column. This work confirmed that gold nanoparticles are promising electrochromatographic support to enhance the phase ratio of open‐tubular capillary electrochromatography column in capillary electrochromatography.

Recent developments of monolithic and open‐tubular capillary electrochromatography (2017–2019)

“…The β‐CD and derivatives have attracted extensive attentions and been used as the most popular chiral selectors in CEC , because they have the advantages of inexpensive, providing a fast equilibration of the CD‐solute complex, high efficiency, and a better peak symmetry . Guo et al.…”

“…Zhen et al. prepared a β‐CD‐AuNPs coated OT‐CEC column through the feasible sol–gel method and characterized using FTIR spectroscopy, Brunner–Emmet–Teller measurements (BET), and SEM. Three enantiomers, including chlorphenamine, brompheniramine, and pheniramine, were baseline separated.…”

“…Advanced biomaterials offered multiple opportunities to promote the development of OT‐CEC for the separation of chiral compounds and some proteins. Different from the chiral resolution material β‐CD, which are prepared through covalent bonding and sol–gel methods due to their easy modification, biomaterials based OT columns are usually prepared through in situ grow or self‐assembled . Inspired by the role of fibrin in natural blood clotting, Xiao et al.…”

Preparation of a thiols β‐cyclodextrin/gold nanoparticles‐coated open tubular column for capillary electrochromatography enantioseparations

“…Compared to packed or monolithic column CEC, the main advantages of OT columns is its simple preparation process, high efficiency, and short conditioning time [7]. However, OT columns has evident disadvantage including the relatively low phase ratio and sample capacity due to the typical small surface area of the coating [8], which hinders its applications. To increase the inner surface area of OT column, several options such as sol‐gel techniques, porous layers, etching, and nanoparticle phases have been developed [9–12].…”

Preparation and evaluation of biselector bonded‐type multifunctional chiral stationary phase based on dialdehyde cellulose and 6‐monodeoxy‐6‐monoamino‐β‐cyclodextrine derivatives

“…[32][33][34][35] As a chiral selector, DAC has been applied as HPLC CSPs, which proves that DAC has both chiral and achiral separation ability. 36 Cyclodextrins are one of the most commonly used chiral selectors in HPLC for enantioseparation 37,38 due to their ability to form host-guest inclusion with a large variety of chiral compounds. In addition, cyclodextrins could achieve good separations for diastereomers, geometric isomers, and polynuclear aromatic compounds.…”