Zeta potential arises from fact that ions tend to be adsorbed on surface of cell walls. This potential interfaces with electric field sensed by migrating particles and degrades resolution of separation. By regulating sign and magnitude of applied potential induced charge can be used to increase or decrease effective wall zeta potential

Fogal, G. L.

English

NASA Technical Reports Server

Cell 
Electrode 
Insulating 
Layer 
August 1973	 B73-10260 
•	 NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Zeta Potential Control for Electrophoresis Cells 
In electrophoresis cells, particles in an electrolyte are 
subjected to an electric field. The particles begin to 
move toward the electrode of opposite charge, the rate 
of migration being different for different kinds of 
particles. This phenomenon is frequently used in bio-
chemistry to separate mixtures of proteins or other 
substances. Because each species migrates at a different 
rate, zones of each different species are formed. 
One of the factors affecting the resolution in this 
technique is the "zeta potential". It arises from the 
fact that ions tend to be adsorbed on the surface of the 
cell walls. It is generally thought that this causes the 
formation of a double layer of closely held dehydrated 
ions and of diffused hydrated ions along the cell wall. 
This layer acts much like a capacitor and has an 
electrokinetic potential often called the "zeta potential". 
This zeta potential tends to interfere with the 
electric field sensed by the migrating particles and 
degrades the resolution of the separation. However,
each particle has a similar zeta potential arising from 
the presence of a hydrated sphere surrounding it. If the 
zeta potential of the cell wall can be made to match that 
of the particles, the effect of the cell walls on the 
migration can be considerably reduced. 
The wall zeta potential can be controlled by the 
addition of an electrically insulated conductor along the 
cell walls. A positive or negative electric potential 
applied to the conductor induces a charge of opposite 
sign on a thin insulating layer. By regulating the sign and 
magnitude of the applied potential, the induced charge 
can be used to increase or decrease the effective wall 
zeta potential. This is the technique shown in the 
illustration. The thin conductor is a layer sandwiched 
between the insulating cell wall and a layer of insulation 
that becomes the new interior cell wall. To match the 
wall potential to zones of different species in the 
mixture, the conductor layer may comprise two or 
more independently controlled segments. 
(',.II lAI..II
S	 Electrophoresis Cell With Zeta Potential Control
(continued overleaf) 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States 	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19730000260 2020-03-17T07:14:14+00:00Z
Note:	 Patent status:	 - 
No further documentation is available. Specific ques
.	 Inquiries concerning rights for the commercial use of tions, however, may be directed to:
	 this invention should be directed to: 
Technology Utilization Officer
	 Patent Counsel 
Marshall Space Flight Center
	 Marshall Space Flight Center Code A&PS-TU	 Code A&PS-PAT 
Marshall Space Flight Center, Alabama 35812
	 Marshall Space Flight Center, Alabama 35812 Reference: B73-10260
Source: G. L. Fogal of

General Electric Co.

under contract to

Marshall Space Flight Center

(MFS-22333)
. 
. 
B73-10260
Category 04


Zeta potential control for electrophoresis cells

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