Capillary electrophoresis technique

MECC has also been reported to be an effective method for the separation of enantiomers [269, 270]. Tsai et al. [271] reported y-cyclodextrin-modified micellar capillary electrophoresis technique for the separation of dansylated-DL-amino acids. 

Fig. 5.4.12a-d Electropherograms of pure standards containing nine BA conjugates at a concentration of 50 nmol/ml (a), a blank serum sample from a healthy subject (b), the same serum sample spiked with 50 nmol/ml of nine different BAs (c) and serum sample from a patient with chronic hepatitis infection (d) analyzed by the capillary electrophoresis technique. Ultraviolet absorbance detection at 195 nm (reprinted from [30])... 

A. W. Moore-Jr, J. P. Larmann-Jr, A. V. Lemmo and J. W. Jorgenson, Two-dimensional liquid chromatography-capillary electrophoresis techniques for analysis of proteins and peptides , Methods Enzymol. 270 401-419 (1996). 

Other modifications of capillary electrophoresis techniques, described below, have been adopted for the improvement of separation of several substances, including proteins, peptides and aminoacids. Furthermore, new procedures are also being developed to avoid the adsorption of proteins and peptides onto the walls of the capillary and consequently improving their selectivities. 

Huang, Z., Timerbaev, A.R., Keppler, B.K., Hirokawa, T. Determination of cisplatin and its hydrolytic metabolite in human serum by capillary electrophoresis techniques. J. Chromatogr. A 1106, 75-79 (2006)... 

Table 4-11. Capillary electrophoresis techniques and their applications...

Boutin, J. A., Hennig, P., Lambert, P. H., et al. (1996) Combinatorial peptide libraries Robotic synthesis and analysis by nuclear magnetic resonance, mass spectrometry, tandem mass spectrometry, and high-performance capillary electrophoresis techniques. Anal. Biochem. 234, 126-141. 

D. R. Baker, Capillary Electrophoresis, Techniques in Analytical Chemistry Series, John Wiley Sons, New York, 31. 1995. 

B. Volland, J.P f auchbre, J.L. Combinatorial Peptide Libraries Robotic Synthesis and Analysis by Nuclear Magnetic Resonance, Mass Spectrometry, Tandem Mass Spectrometry, and High-performance Capillary Electrophoresis Techniques, AnflZ. Biochem. 234, 126-141 (1996). 

These preclinical drug metabolism studies may also include metabolite profiling in plasma, selected tissues, urine, and bile to assess the distribution and disposition of potentially important metabolites, such as those having a level 5% or greater relative to the parent compound. Metabolite profiling requires a technique to separate the parent compound from metabolites and other endogenous compounds. For small organic molecules, HPLC is usually the method of choice. For macromolecules, gel or capillary electrophoresis techniques can be defined with sufficient resolution capability to separate the... 

A consumer has complained that the contents of one can of their diet soft drink had a peculiar taste. It has been given to you to determine what is causing this off-taste. The can has no expiration date so it could be just "old pop", or it could be something more serious. You decide to determine if the problem could be just sweetener breakdown by using a micellar capillary electrophoresis technique. 

The MLC limitations were clearly seen during this symposium when the capabilities of the micellar phases associated with the then new capillary electrophoresis technique were exposed. Electropherograms showing efficiencies in the 100,000 plates/m range were displayed [37]. 

However, the capillary electrophoresis technique provides a simple solution to the problem of Joule heating that results in poor resolution. The microchannel of a capillary has such a high surface-area-to-volume ratio that the heat is efficiently dissipated via the capillary wall. 

Capillary electrophoresis techniques have been applied to orthophosphate analysis (Table 8.2). While generally offering much faster separations of anions in waters than say ion chromatography, CE with conventional UV detection suffers from a lack of sensitivity. However, use of on-capillary preconcentration using isotachophoresis [142,143] has enabled sub-pg detection limits to be achieved in high ionic strength matrices, and this approach is a promising one for water analysis. 

Monosodium glutamate determination in food has been performed by chromatographic techniques [10]. However, these methods involve time-consuming procedures and require extensive and laborious sample treatment. Usually, derivatization pre- or postcolumn is needed to increase the sensitivity of the method [11]. In most, postcolunm derivatization strategy with o-phthalaldehyde-2-mercaptoethanol is used for this analyte in the isocratic elution mode due to a faster reaction [12]. Actually, chromatography and capillary electrophoresis techniques have mainly been employed to determine glutamate in biological samples in which low limits of detection are needed. 

---