High-speed Enantioseparation by Microchip Electrophoresis

Microchip electrophoresis (MCE) has been recognized as an important separation technique on the research field of micro total analytical systems (μ-TAS) since the first publication on MCE was reported by Manz et al. in 1992 [1]. In MCE, there are several advantages, e.g., high speed analysis in seconds, small amount of sample, high separation efficiency, and high-throughput analysis by using microchips with highly integrated multi-separation channels, which provides superior performance especially for the analysis of biogenic compounds. Since these characteristics in MCE are very suitable for the analysis of enantiomers which often requires higher separation efficiency, the MCE method is expected to be applied to the high-throughput chiral analysis systems. In capillary electrophoresis (CE) analysis of enantiomers, both electrokinetic chromatography (EKC) using cyclodextrins (CDs) as a chiral selector and capillary electrochromatography analysis with stationary phase packed or coated capillaries are generally employed. In the MCE analysis of enantiomers, on the other hand, cyclodextrin EKC (CDEKC) has been mainly applied, which attained the enantioseparation of amino acids, biogenic amines, amphetamines, arylpropionic acids, and so on [2]. In the MCE chiral analysis, the selection of the detection scheme is considerably important. When laser-induced fluorescence (LIF) spectrometry is employed as a detection scheme, a fluorescent derivatization of analytes is sometimes troublesome to reduce chiral recognition ability between selectors and analytes. In the case of off-channel detector configuration, which is primarily employed in electrochemical (EC), electroconductivity (ECD), and chemiluminescence (CL) detection, on the other hand, the separation efficiency is reduced by a dead volume formed between the separation channel and detector. Thus, the detection scheme strongly affects the chiral resolution in MCE. In this article, the chiral analysis in MCE is reviewed, mainly microchip CDEKC (MC−CDEKC), with categorizing by the detection methods. Focusing Review