Recent advances in electrodriven enantioseparations

Abstract

Capillary electromigration techniques have developed into significant analytical separation tools especially for enantioseparations. While CE can be considered a mature technique as documented by its wide applications, CEC is still in a developmental state despite many research efforts. The success of stereospecific CE separation methods is due to the high specificity and flexibility of the technique as well as the availability of many types of chiral selectors. Thus, numerous methods have been developed for the analysis of chiral compounds in chemical, biochemical, pharmaceutical, environmental, and forensic sciences. However, most reported applications deal with pharmaceuticals. The search for new chiral selectors also continued despite the fact that most applications were performed using cyclodextrins. Furthermore, CE has been combined with spectroscopic and molecular modeling studies in attempts to understand the interactions between chiral selectors and analytes. The present review focuses on recent examples of mechanistic aspects of capillary enantioseparations with regard to mathematical modeling of enantioseparations, investigations of the analyte-complex structures as well as new chiral selectors and applications of chiral analyses by CE and CEC. It covers the literature published between January 2011 and August 2012.

Study on the separation of ofloxacin enantiomers by hydroxyl-propyl-β-cyclodextrin as a chiral selector in capillary electrophoresis: a computational approach

“…Customarily, in CE addition of chiral selectors to the background electrolyte (BGE) facilitated resolution of a huge number of chiral compounds. A glance at the literature can easily reveal the fact that macrocycle antibiotics and cyclodextrins are the most dominantly utilized running buffer additives [1,3,[5][6][7][8][9][10][11][12]. So far the general mechanism adopted for the chiral resolution is the one based on the formation of transient diastereoisomers that exhibit different thermodynamic stability with an ensuing difference in migration times.…”

“…Additionally, the pressing demand for pure chiral compounds has led to the development of various synthetic and separation procedures. Due to its high efficiency, simplicity, and versatility capillary electrophoresis (CE) technique has emerged as an appealing choice for enantioseparations, where small amount of samples and additives are used [1][2][3][4][5]. Customarily, in CE addition of chiral selectors to the background electrolyte (BGE) facilitated resolution of a huge number of chiral compounds.…”

An integrated microfluidic chip enabling control and spatially resolved monitoring of temperature in micro flow reactors

“…Particularly attractive about this technology is the possibility to combine different processes, e.g., chemical synthesis [9][10][11][12][13][14][15][16][17] and analytical observation [18][19][20][21][22][23][24][25][26][27] in a dead-volume-free manner on a single substrate [28,29]. The prospect of using only tiny amounts of precious chemicals in integrated chips opens up new avenues for the exploration of novel synthetic routes and the exploration of chemical diversity.…”

Chiral separation of d/l-aldoses by micellar electrokinetic chromatography using a chiral derivatization reagent and a phenylboronic acid complex

“…In CE, chiral selectors such as cyclodextrins [9,10], crown ethers [11], and ligand exchangers [12] act as a pseudostationary phase that may possess its own unique mobility, allowing implementation of different separation scenarios that contribute to the high flexibility of CE. Further advantages of CE include the low consumption of chemicals and the high separation efficiency [13]. Another useful approach is the separation of diastereomers formed by derivatization of racemic compounds with an optically pure reagent.…”