Modeling of formation and prevention of a pure water zone in capillary isoelectric focusing with narrow pH range carrier ampholytes

This paper comprises a continuation of computer simulation studies dealing with carrier ampholyte based CIEF in presence of narrow pH gradients. With this technique, amphoteric sample components with p I values outside the pH gradient are migrating isotachophoretically toward the cathode or anode whereas components with p I values within the gradient become focused. In order to understand the processes occurring in presence of the electric field, the behavior of both carrier ampholytes and amphoteric sample components is investigated by computer modeling. Characteristics of two pH unit gradients with end components having p I values at or around 7.00 and conditions that lead to the formation of a water zone at neutrality were investigated. Data obtained reveal that a zone of water is formed in focusing with carrier ampholytes when the applied pH range does not cover the neutral region, ends at pH 7.00 or begins at pH 7.00. The presence of additional amphoteric components that cover the neutrality region prevent water zone formation under current flow. This situation is met in experiments with narrow pH gradients that end or begin around neutrality. Simulation data reveal that no water zone evolves when atmospheric carbon dioxide dissolved in the catholyte causes the migration of carbonic acid (in the form of carbonate and/or hydrogen carbonate ions) from the catholyte through the focusing structure. An electrolyte change in the electrode solution does not have an impact on the focusing part but does change the isotachophoretic pattern migrating behind the leading ion..

Medienart:

Artikel

Erscheinungsjahr:

2017

Erschienen:

2017

Enthalten in:

Zur Gesamtaufnahme - volume:38

Enthalten in:

Electrophoresis - 38(2017), 5, Seite 677-688

Sprache:

Englisch

Beteiligte Personen:

Takácsi‐Nagy, Anna [VerfasserIn]
Kilár, Ferenc [Sonstige Person]
Thormann, Wolfgang [Sonstige Person]

Links:

Volltext
onlinelibrary.wiley.com

BKL:

35.29

Themen:

Carbonic acid
Carrier ampholytes
Isoelectric focusing
Narrow pH gradient
Simulation
Water zone

doi:

10.1002/elps.201600314

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

OLC1993272682