Micellar electrokinetic chromatography capillary zone electrophoresis with

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. 

Ackermans, M. T., Everaerts, F. M., and Beckers, J. L. (1992). Determination of aminoglycoside antibiotics in pharmaceuticals by capillary zone electrophoresis with indirect UV detection coupled with micellar electrokinetic capillary chromatography.. Chromatogr. 606, 229—235. 

Versatility of CE separation modes zone electrophoresis (CZE), micellar electrokinetic chromatography (MEKC), gel electrophoresis (CGE), isotachophoresis (CITP), isoelectric focusing (CIEF), capillary electrochromatography (CEC, a hybrid with HPLC), and last but not least Affinity CE (ACE)... 

Capillary Electrophoresis (CE) and Micellar Electrokinetic Chromatography (MEKC). - Di(2-ethylhexyl) thiophosphoric acid (DEHTPA) has been earlier characterised by potentiometric titration, and quantified by capillary zone electrophoresis with carbonate buffer, operating at —20 kV, and using UV detection at 210 nm. ° Also, a comparison has been made of capillary electrophoresis (CE) and liquid chromatography (LC) for the enantiomeric separation of a-phosphonosulfonic acids, where CE used 3-cyclodextrin as chiral selector in a borate electrolyte. Alkylphosphonic acids, at trace levels in water, have been determined by CE coupled online with flame photomeric detection, and alkylphosphonic acid esters have been separated and determined by CE using indirect UV detection. 

A review on methods for analysis of urinary glycosaminoglycans has covered electrophoresis of enzymically produced di- and oligosaccharides. Micellar electrokinetic capillary chromatography, which is equivalent to capillary zone electrophoresis with a surfactant added to the carrier electrolyte, has been used with u.v. detection for the simultaneous determination of seven water-soluble vitamins including vitamin C and riboflavin phosphate. ... 

Capillary electrophoresis is increasingly used in food analysis due to its separation performance combined with the short time of analysis. - CapiUary electrophoresis recently applied to colorant measurements includes technical variants such as capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography. ... 

Xue, G., Pang H.-M., and Yeung E.S., Multiplexed capillary zone electrophoresis and micellar electrokinetic chromatography with internal standardization, Anal. Chem. 71, 2642, 1999. 

Solinova V, Kasicka V, Koval D et al (2004) Analysis of synthetic derivatives of peptide hormones by capillary zone electrophoresis and micellar electrokinetic chromatography with ultraviolet-absorption and laser-induced fluorescence detection. J Chromatogr B 808 75-82... 

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. 

The first and most often encountered separation mechanism in CE is based on mobility differences of the analytes in an electric field these differences are dependent on the size and charge-to-mass ratio of the analyte ion. Analyte ions are separated into distinct zones when the mobility of one analyte differs sufficiently from the mobility of the next. This mechanism is exemplified by capillary zone electrophoresis (CZE) which is the simplest CE mode. A number of other recognized CE modes are variations of CZE. These are micellar electrokinetic capillary chromatography (MECC), capillary gel electrophoresis (CGE), capillary electrochromatography (CEC), and chiral CE. In MECC the separation is similar to CZE, but an additional mechanism is in effect that is based on differences in the partition coefficients of the solutes between the buffer and micelles present in the buffer. In CGE the additional mechanism is based on solute size, as the capillary is filled with a gel or a polymer network that inhibits the passage of larger molecules. In chiral CE the additional separation mechanism is based on chiral selectivity. Finally, in CEC the capillary is packed with a stationary phase that can retain solutes on basis of the same distribution equilibria found in chromatography. 

Various papers related to the simultaneous determination of creatinine and uric acid can be found in the hterature. Several authors have developed capillary zone electrophoresis (CZE) methods for simultaneous analysis of these compounds in urine. The CE analysis of these renal markers offers some advantages when compared with chromatography, such as shortened separation time, reduced reagent consumption, and increased resolution. Capillar micellar electrokinetic chromatography has been applied to the simultaneous separation of creatinine and uric acid in human plasma and urine. However, chromatographic techniques are widely accepted for the determination of these compounds. Reversed-phase and ion... 

The technique is therefore particularly suited to water-soluble species which possess a charge, which includes most dyes. Variations from the main technique (often referred to as capillary zone electrophoresis, CZE) do exist and these include the use of surfactants in the buffer to create micelles (often thought of as creating a pseudo-stationary phase inside the capillary) which then improve the separation of neutral species (and frequently charged molecules) owing to hydrophobic interactions. The term micellar electrokinetic chromatography (MECC or MEKC) is often used for CE separations carried out with the aid of a micellar buffer solution. 

Capillary electrophoresis (CE) is an emerging analytical technique for determination of catechins. The majority of CE studies involve the analysis of catechins in tea infusion, extracts as well as supplements. The three variants of CE suitable for the analysis of catechins include capillary zone electrophoresis (CZE), micellar electro-kinetic chromatography (MEKC), and microemulsion electrokinetic chromatography (MEEKC) with UV detection. In general, the resolution of MEKC was found to be superior to CZE for separation of catechins. MEEKC is a relatively new technique, and the few reports available suggest that it offers a performance similar to MEKC. CE conditions are often quite complex, and many factors, such as buffer composition, pH, presence of surfactants, and column temperature, can all affect the quality of separation and should be optimized individually. On the other hand, CE offers several advantages over HPLC. The short analysis time (<20 minutes), low running costs, and reduced use of solvents make it an attractive alternative for routine analysis of catechins. 

Most CE work so far has been done using the capillary zone electrophoresis (CZE) mode, where analytes are separated on the basis of differences in electrophoretic mobility, which is related to charge density. The separation is carried out in a capillary filled with a continuous background electrolyte (buffer). Micellar electrokinetic capillary chromatography (MEKC or MECC) is one other CE method based on differences in the interaction of the analytes with micelles present in the separation buffer, which can easily separate both charged and neutral solutes with either hydrophobic or hydrophilic properties. An alternative to MEKC is capillary... 

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