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A device for measuring the segmental voltages along electrofocusing gels
Author(s) -
Jackiw B. Andrew,
Chidakel Burt E.,
Chrambach Andreas,
Brown Ray K.
Publication year - 1980
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.1150010206
Subject(s) - isoelectric focusing , voltage , materials science , voltage drop , analytical chemistry (journal) , drop (telecommunication) , chemistry , chromatography , electrical engineering , biochemistry , enzyme , engineering
A device for the measurement of segmental voltages along electrofocusing gels made of polyacrylamide has been designed and tested successfully. It allows for continuous monitoring of the changing voltage gradients which occur during electrofocusing. By means of 11 equidistant embedded platinum probes, the voltage drop at any one segment or sequential array of segments can be determined at any time without disturbing the ongoing electrofcusing. The wires are sealed into the wall of a 6 mm diameter (ID) Pyrex gel tube at 1.0 cm intervals. Measurements on a gel containing 2% Ampholine (pH‐range 3.5–10) showed that the voltage gradient changes during electrofocusing. Starting with a uniform voltage drop of 10 ± 2%cm across a 10 cm gel, two transient peaks of high potential (comprising at 15 min 17% and 25% of the applied voltage) move progressively from the gel periphery toward its center. They coalesce into a broad single peak centered at 0.4 of the distance from the anodic gel terminus within 1.5 h. This major single peak remained stationary, changing slightly in magnitude during the next 18 h of electrofocusing. At this final stage, the voltage peak occurred at pH 6.3 and approximately 25% of the applied voltage was across this segment of gel.