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The electric field strength across isoelectric focusing gel slabs determined by an accurate and convenient method
Author(s) -
Murel Andrei,
Vilde Svetlana,
Kongas Ago,
Kirret Oskar
Publication year - 1984
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150050303
Subject(s) - isoelectric focusing , voltage , voltmeter , chemistry , joule heating , electrode , analytical chemistry (journal) , electric field , materials science , chromatography , composite material , electrical engineering , physics , enzyme , engineering , biochemistry , quantum mechanics
A simple and accurate method for the monitoring of the voltage distribution across horizontal slab gels in isoelectric focusing is described. Voltage is measured by passing a single Pt wire electrode (connected to an external voltmeter and to one of the electrodes through the power supply) through holes in the apparatus lid, bored at 5 mm distance from one another across the migration path. Conductances along the migration path calculated from direct voltage measurements are by one order of magnitude lower than those measured by conductimetry on gel slice eluates. Segmental resistances calculated from the measured voltages across adjacent holes in the lid during isoelectric focusing (IEF) add up to the total resistances across the gel obtained from the voltage and current readings on the power supply. In confirmation of previous reports, segmental resistance in IEF was shown to increase dramatically with time, with maxima shifting progressively from pH 4 to 5 in a representative pH3‐10 gradient. Joule heat production in IEF decreases with increasing molecular weight of the carrier ampholytes.