Instabilities of the pH gradient in carrier ampholyte-based isoelectric focusing: Elucidation of the contributing electrokinetic processes by computer simulation.

Thormann, Wolfgang; Mosher, Richard A (2021). Instabilities of the pH gradient in carrier ampholyte-based isoelectric focusing: Elucidation of the contributing electrokinetic processes by computer simulation. Electrophoresis, 42(7-8), pp. 814-833. Wiley-VCH 10.1002/elps.202000269

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Electrokinetic processes that lead to pH gradient instabilities in carrier ampholyte-based IEF are reviewed. In addition to electroosmosis, there are four of electrophoretic nature, namely (i) the stabilizing phase with the plateau phenomenon, (ii) the gradual isotachophoretic loss of carrier ampholytes at the two column ends in presence of electrode solutions, (iii) the inequality of the mobilities of positively and negatively charged species of ampholytes, and (iv) the continuous penetration of carbonate from the catholyte into the focusing column. The impact of these factors to cathodic and anodic drifts was analyzed by simulation of carrier ampholyte-based focusing in closed and open columns. Focusing under realistic conditions within a 5 cm long capillary in which three amphoteric low molecular mass dyes were focused in a pH 3-10 gradient formed by 140 carrier ampholytes was investigated. In open columns, electroosmosis displaces the entire gradient toward the cathode or anode whereas the electrophoretic processes act bidirectionally with a transition around pH 4 (drifts for pI > 4 and pI < 4 typically toward the cathode and anode, respectively). The data illustrate that focused zones of carrier ampholytes have an electrophoretic flux and that dynamic simulation can be effectively used to assess the magnitude of each of the electrokinetic destabilizing factors and the resulting drift for a combination of these effects. Predicted drifts of focused marker dyes are compared to those observed experimentally in a setup with coated capillary and whole column optical imaging.

Item Type:

Journal Article (Review Article)

Division/Institute:

04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases

UniBE Contributor:

Thormann, Wolfgang

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

0173-0835

Publisher:

Wiley-VCH

Language:

English

Submitter:

Wolfgang Thormann

Date Deposited:

19 Jan 2021 14:30

Last Modified:

21 Apr 2021 01:32

Publisher DOI:

10.1002/elps.202000269

PubMed ID:

33184847

Uncontrolled Keywords:

Cathodic drift Electroosmosis Isoelectric focusing Isotachophoresis Simulation

BORIS DOI:

10.48350/150384

URI:

https://boris.unibe.ch/id/eprint/150384

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