First method involves remote adjusting of zeta potential. Second approach sandwiches two conducting metal plates between opposite cell walls and thin insulating layer. Third method forces buffer to flow in direction opposite particle streams

Fogal, G. L.

Mccreight, L. R.

English

NASA Technical Reports Server

May 1974	 f	 B74-10032 
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. 
Methods for Improved Resolution of Flow Electrophoresis Cells 
One basic factor affecting the resolution of particle 
streams in electrophoresis flow cells isithe zeta potential. 
This potential results from ions that are adsorbed on the 
surfaces of the cell walls, and interfere with the electric 
field sensed by the migrating particles. The net effect is 
poor resolution or separation among different particle 
species. However, each particle of a given species has a 
similar zeta potential produced from the surrounding 
hydrated sphere. If the zeta potential of the cellwall can 
be made to match those of the particles, the inter-
ference from the cell walls could be reduced con-
siderably, enhancing the resolution. Wall coatings that 
could provide desired zeta potentials are usually in-
compatible with electrophoretic equipment. 
Three approaches have been-developed to improve this 
resolution. One method involves a remotely-adjustable 
zeta potential. In this technique, an adjustable high-
voltage electrical field is provided by two metal plates 
located, respectively, above and below the large faces of 
the electrophoresis cell. The electric field established by 
these plates is perpendicular to the faces and also to the 
direction of particle flow. By the proper adjustment of 
electrical field magnitude and sign, the cross sections of 
particle streams are compressed and centered. As a 
result of these reduced-flow cross sections, particle 
streams of different species become more separated, 
yielding improved resolution. 
The second method, similar to the first, produces 
essentially the same effect. In this scheme, two con-
ducting metal plates are sandwiched between the oppo-
site cell walls, and a thin insulating layer. The opposing 
thin layers become part of the interior cell wall. A 
positive or a negative potential applied to either plate 
induces a charge of opposite sign on its interior 
insulator. Again, by regulating the sign and the magni-
tude of the applied potential, the induced charge 
increases or decreases the effective wall zeta potential.
The third method entails a counterfiow buffer. In 
this case, the buffer is forced to flow in a direction 
opposite to the particle streams. The counterfiow 
separates the particle streams, effectively reducing the 
normal time required for this separation. The result is 
improved resolution among the particle streams per 
given cell length. 
Notes: 
1. Either one of the first two methods may be used in 
conjunction with the counterfiow technique to im-
prove the resolution further. 
2. Requests for further information may be directed to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&PS-TU 
Marshall Space Flight Center, Alabama 35812 
Reference: B74-10032 
Patent status: 
Inquiries concerning rights for the commercial use of 
this invention should be addressed to: 
Patent Counsel 
Marshall Space Flight Center 
Code A&PS-PAT 
Marshall Space Flight Center, Alabama 35812 
Source: L. R. McCreight and

G. L. Fogal of
General Electric Co. 
under contract to 
Marshall Space Flight Center

(MFS.22223) 
S
Category 04,05,02 
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 Stales	 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.
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Methods for improved resolution of flow electrophoresis cells

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