Native and substituted cyclodextrins as chiral selectors for capillary electrophoresis enantioseparations: Structures, features, application, and molecular modeling

Abstract

CDs are cyclic oligosaccharides consisting of α‐d‐glucopyranosyl units linked through 1,4‐linkages, which are obtained from enzymatic degradation of starch. The coexistence of hydrophilic and hydrophobic regions in the same structure makes these macrocycles extremely versatile as complexing host with application in food, cosmetics, environmental, agriculture, textile, pharmaceutical, and chemical industries. Due to their inherent chirality, CDs have been also successfully used as chiral selectors in enantioseparation science, in particular, for CE enantioseparations. In the last decades, multidisciplinary approaches based on CE, NMR spectroscopy, X‐ray crystallography, microcalorimetry, and molecular modeling have shed light on some aspects of recognition mechanisms underlying enantiodiscrimination. With the ever growing improvement of computer facilities, hardware and software, computational techniques have become a useful tool to model at molecular level the dynamics of diastereomeric associate formation to sample low‐energy conformations, the binding energies between the enantiomer and the CD, and to profile noncovalent interactions contributing to the stability of CD/enantiomer association. On this basis, the aim of this review is to provide the reader with a critical overview on the applications of CDs in CE. In particular, the contemporary theory of the electrophoretic technique and the main structural features of CDs are described, with a specific focus on techniques, methods, and approaches to model CE enantioseparations promoted by native and substituted CDs. A systematic compilation of all published literature has not been attempted.

Comparative studies on enantioseparation of New Psychoactive Substances using cyclodextrin-assisted capillary electrophoresis with UV detection

“…Moreover, they possess low UV-absorption preventing detection problems. This makes cyclodextrins to the most often applied chiral selectors for CE [22].…”

Immunoaffinity Capillary Electrophoresis in the Era of Proteoforms, Liquid Biopsy and Preventive Medicine: A Potential Impact in the Diagnosis and Monitoring of Disease Progression

“…The basic principle of capillary electrophoresis is the separation of ions based on their electrophoretic mobility (mass/charge ratio) with the use of an applied voltage. Capillary electrophoresis can separate a wide range of chemical and biochemical entities, including neutral substances, cellular and subcellular entities, and nanoparticles or nanovesicles using one or more of 9 different separation modes [144][145][146][147][148][149][150][151]. Because of this, CE is known for its high-power resolution, high sensitivity and rapidity, high peak capacity, high separation efficiency with reproducible quantification, the use of small sample volumes with low waste generation, on-column and off-column detection, automation, low cost of operation, use of miniaturized components, option of multiple detection systems, and a diverse range of applications [144][145][146][147][148][149][150][151].…”

“…Furthermore, using narrow capillaries helps to reduce band-broadening seen in the peaks generated in other techniques such as high-performance liquid chromatography (HPLC). As a result, separation efficiency in CE is very high [144][145][146][147][148][149][150][151]. As opposed to conventional electrophoresis, which is labor-intensive and can take several hours to perform, CE can be completely automated and only a few microliters of sample are needed for an analysis to be carried out in a few minutes [123,151].…”

The Use of Antibiotics as Chiral Selectors in Capillary Electrophoresis: A Review

“…CDs are by far the most popular, useful, and successful CSs in CE due to their commercial availability, relatively affordable prices, low UV absorbance, stability over a wide pH range, and high capacity of complexation towards a large number of pharmaceuticals [ 11 , 12 , 13 ].…”