Isotachophoretic zone formation of serum albumin in different free fluid electrophoresis instruments

Thormann, Wolfgang; Firestone, Millicent A.; Sloan, Jeffrey E.; Long, Terry D.; Mosher, Richard A.

doi:10.1002/elps.1150110405

Cited by 25 publications

(14 citation statements)

References 12 publications

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“…4) only. In that experiment, a constant current of 50 mA was applied (current density: 635 A/mZ, a value that is similar to that employed for CITP, as described above, and in RITP of proteins [36]), the voltage increased from 330 to 680 V, and counterflow was applied after 12 min of power application and lasted for 59 min, i.e., up to the time of sample collection. As expected, methadone was determined to behave isotachophoretically, i.e., methadone placed itself between leader and terminator.…”

Section: Ritp Of Methadone Enantiomers In the Miniphormentioning

confidence: 99%

Enantiomeric separation of methadone by cyclodextrinbased capillary and recycling isotachophoresis

1998

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The separation of methadone enantiomers by cationic capillary isotachophoresis (CITP) and recycling isotachophoresis (RITP) having (2-hydroxypropyl)-beta-cyclodextrin (OHP-beta-CD) as chiral selector in the leading electrolyte is described. Sodium acetate/acetic acid (pH between 4 and 5) served as leading electrolyte (catholyte) and acetic acid as terminator (anolyte). Complete separation of the enantiomers was obtained by CITP in a 50 microm internal diameter (ID) fused-silica capillary and in a 500 microm ID Teflon capillary. In the first approach, enantiomeric separation could be monitored via UV absorbance detection at low wavelength. With the second instrumental setup, an additional conductivity sensor permitted the visualization of the enantiomeric separation and the characterization of the buffer system employed. A 10 mM sodium acetate/acetic acid leading buffer of pH 4.3, containing 5 mM OHP-beta-CD, was found to provide best enantiomeric separation and was thus chosen for RITP. With RITP processing of a few mg of racemic methadone, partial separation of methadone enantiomers was obtained. R-(-)-methadone and S-(+)-methadone were found to be significantly (up to about 80%) enriched at the front and back side, respectively, of the isotachophoretic zone. The enantiomeric composition of methadone in the collected fractions was assessed by chiral capillary zone electrophoresis (CZE) and circular dichroism spectroscopy. CZE was found to represent a simple and efficient method for the determination of the enantiomeric excess, whereas the latter technology was noted to be the superior approach for properly characterizing fractions that contain similar amounts of the two enantiomers. Furthermore, chiral RITP and analysis of the collected fractions by circular dichroism spectroscopy is shown to be potentially useful for identification of single enantiomers in absence of pure chiral standards.

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Section: Ritp Of Methadone Enantiomers In the Miniphormentioning

confidence: 99%

Enantiomeric separation of methadone by cyclodextrinbased capillary and recycling isotachophoresis

1998

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“…A CIEF analysis of a monoclonal antibody using an optimized protocol with focusing in quiescent solution (neutral capillary) followed by chemical mobilization is depicted in Figure 19. In isotachophoresis of protein zones of rather high concentration (typically of the order of 10 to 20 mg/mL provided that there is enough material present [159]) are formed and CITP is employed to preconcentrate (sharpen) protein zones prior to their separation by CZE or CE-MS.…”

Section: Ce Of Peptides and Proteinsmentioning

confidence: 99%

Capillary and Microchip Electrophoresis

Thormann

2012

Ullmann's Encyclopedia of Industrial Chemistry

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“…This was attributed to additional protein interactions which are not considered in the model. In subsequent work, Thormann et al [155] performed simulations of ITP separations of serum albumin and compared these with experimental capillary ITP, continuous flow ITP and recirculating flow ITP in various instruments. Distortion of protein zones found in the collected fractions of continuous flow ITP, which was not observed for low molecular mass compounds and was not observed in the simulations, was attributed to the high density/viscosity gradient formed at the buffer interfaces as well as the design of the outlet ports.…”

Section: Aspects Of Itp and Mbementioning

confidence: 99%

Dynamic computer simulations of electrophoresis: A versatile research and teaching tool

et al. 2010

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Software is available, which simulates all basic electrophoretic systems, including moving boundary electrophoresis, zone electrophoresis, ITP, IEF and EKC, and their combinations under almost exactly the same conditions used in the laboratory. These dynamic models are based upon equations derived from the transport concepts such as electromigration, diffusion, electroosmosis and imposed hydrodynamic buffer flow that are applied to user-specified initial distributions of analytes and electrolytes. They are able to predict the evolution of electrolyte systems together with associated properties such as pH and conductivity profiles and are as such the most versatile tool to explore the fundamentals of electrokinetic separations and analyses. In addition to revealing the detailed mechanisms of fundamental phenomena that occur in electrophoretic separations, dynamic simulations are useful for educational purposes. This review includes a list of current high-resolution simulators, information on how a simulation is performed, simulation examples for zone electrophoresis, ITP, IEF and EKC and a comprehensive discussion of the applications and achievements.

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Isotachophoretic zone formation of serum albumin in different free fluid electrophoresis instruments

Cited by 25 publications

References 12 publications

Enantiomeric separation of methadone by cyclodextrinbased capillary and recycling isotachophoresis

Enantiomeric separation of methadone by cyclodextrinbased capillary and recycling isotachophoresis

Capillary and Microchip Electrophoresis

Dynamic computer simulations of electrophoresis: A versatile research and teaching tool

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