Electrochromatography micellar electrokinetic chromatography

Capillary electrophoresis (CE) coupled to MS has the advantage of high resolution and soft ionization for biomolecules, which may be used to differentiate post-translational modifications and variants of intact proteins and oligonucleotides. Different modes of CE (capillary zone electrophoresis, capillary isoelectric focusing, capillary electrochromatography, micellar electrokinetic chromatography, nonaqueous capillary electrophoresis) to MS as well as online preconcentration techniques (transient capillary isotachophoresis, solid-phase extraction, membrane preconcentration) are used to compensate for the restricted detection sensitivity of the CE methodology [77, 78]. 

CE was recently used for anthocyanin analysis because of its excellent resolution. This technique has different modes capillary zone electrophoresis (CZE), capillary gel electrophoresis (CGE), micellar electrokinetic chromatography (MEKC), capillary electrochromatography (CEC), capillary isoelectric focusing (CIEE), and capillary isotachophoresis (CITP)."° CZE is the most popular method for anthocyanin... 

CE is a family of techniques similar to those found in conventional electrophoresis zone electrophoresis, displacement electrophoresis, isoelectric focusing (IEF), and sieving separations. Other modes of operation unique to CE include micellar electrokinetic chromatography (MEKC) and capillary electrochromatography (CEC). 

Dedicated applications of capillary zone electrophoresis (CZE) coupled to MS are discussed, particularly in the field of drug analysis. Development of other capillary-based electrodriven separation techniques such as non-aqueous capillary electrophoresis (NACE), micellar electrokinetic chromatography (MEKC), and capillary electrochromatography (CEC) hyphenated with MS are also treated. The successful coupling of these electromigration schemes with MS detection provides an efficient and sensitive analytical tool for the separation, quantitation, and identification of numerous pharmaceutical, biological, therapeutic, and environmental compounds. 

Giordano, B. C., C. L. Copper, and G. E. Collins. Micellar electrokinetic chromatography and capillary electrochromatography of nitroaromatic explosives in seawater. 

Capillary electrochromatography (CEC) is a rapidly emerging technique that adds a new dimension to current separation science. The major "news" in this method is that the hydrodynamic flow of the eluting liquid, which is typical of HPLC, is replaced by a flow driven by electro-endoosmosis. This increases considerably the selection of available separation mechanisms. For example, combinations of traditional processes such as reversed-phase- or ion-exchange- separations with electromigration techniques are now possible. Also, CEC is opening new horizons in the separation of non-polar compounds, and thus represents an alternative to the widely used micellar electrokinetic chromatography. 

The separation scientist with experience gained from a LC background may tend to limit the modes of electrochromatography to reversed phase (RP), normal phase, ion-exchange and, maybe, size-exclusion. Analysts from an electrophoretic background typically use the term "CE" in a much broader sense to include the main modes of capillary zone electrophoresis, micellar electrokinetic chromatography, capillary gel electrophoresis, isoelectric focusing and isotachophoresis. 

The majority of enantioseparations are performed by pressure-driven liquid chromatography. However, in the last decade other liquid-phase separation techniques have evolved and demonstrated their usefulness for enantioseparations, including supercritical fluid chromatography (SFC), capillary electrophoresis (CE), micellar electrokinetic chromatography (MEKC), and open-tubular and packed-bed electrochromatography (OT-EC and CEC). 

Abbreviations CZE capillary zone electrophoresis MECC or MEKC micellar electrokinetic chromatography CGE capillary gel electrophoresis CIEF capillary isoelectric focusing CEC capillary electrochromatography DAD Diode-array detection... 

Microextractions have the capability to concentrate selectively compounds with particular chemical properties, and to reject solutes with other particular chemical properties. Microextractions function on a small volume scale. As the volumes involved in microextraction and CE can be (but are not necessarily) the same, and given the capability of microextraction to concentrate analytes selectively, microextractions are a natural choice for improving virtually any CE (micellar electrokinetic chromatography, MEKC capillary electrochromatography, CEC etc.) method. 

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