Chiral Capillary Electrophoresis-Mass Spectrometry

Applications of Capillary Electrophoresis-Mass Spectrometry to Chiral Analysis

Capillary electrophoresis (CE) is a technique that has already proven its importance in the separation of enantiomers. The combination of CE with mass spectrometry (MS) detection further boosts the possibilities of CE in terms of achieving higher sensitivity with the possibility of an unambiguous assignment of analytes of interest. This chapter details four different examples using CE in the electrokinetic chromatography (EKC) mode coupled to MS with application to four different fields of analysis (pharmaceutical, biomedical, food, and agrochemical). The first two methods are based on the use of a single and a double chiral selector system, respectively, in which the partial filling technique (PFT) had to be used to avoid MS-source contamination. In the last two examples, PFT was not needed as they were based on the use of low concentrations of chiral selector but a derivatization step was necessary to allow proper enantiorecognition with the chiral selectors. Description of these protocols is fully explained.

Chiral Capillary Electrokinetic Chromatography: Principle and Applications, Detection and Identification, Design of Experiment, and Exploration of Chiral Recognition Using Molecular Modeling

This work reviews the literature of chiral capillary electrokinetic chromatography from January 2016 to March 2021. This is done to explore the state-of-the-art approach and recent developments carried out in this field. The separation principle of the technique is described and supported with simple graphical illustrations, showing migration under normal and reversed polarity modes of the separation voltage. The most relevant applications of the technique for enantioseparation of drugs and other enantiomeric molecules in different fields using chiral selectors in single, dual, or multiple systems are highlighted. Measures to improve the detection sensitivity of chiral capillary electrokinetic chromatography with UV detector are discussed, and the alternative aspects are explored, besides special emphases to hyphenation compatibility to mass spectrometry. Partial filling and counter migration techniques are described. Indirect identification of the separated enantiomers and the determination of enantiomeric migration order are mentioned. The application of Quality by Design principles to facilitate method development, optimization, and validation is presented. The elucidation and explanation of chiral recognition in molecular bases are discussed with special focus on the role of molecular modeling.