Related Experiment Video
Updated: Jun 19, 2026
20:38
AC Electrokinetic Phenomena Generated by Microelectrode Structures
Published on: July 28, 2008
ELECTROKINETIC PHENOMENA : IV. A COMPARISON OF ELECTROPHORETIC AND STREAMING POTENTIALS
1Laboratory of General Physiology, Harvard University, Cambridge.
The Journal of General Physiology
|October 30, 2009
Summary
Researchers compared electrokinetic potentials using electrophoresis and streaming potentials. A small difference was observed, likely due to variations in protein preparations, not the potentials themselves.
Area of Science:
- Colloid and Surface Science
- Electrochemistry
- Biophysics
Background:
- Electrokinetic potentials are crucial for understanding particle behavior in dispersions.
- Comparing different electrokinetic measurements, such as electrophoresis and streaming potentials, is essential for validating theories.
- Variations in experimental conditions and sample preparation can influence electrokinetic measurements.
Purpose of the Study:
- To establish conditions necessary for comparing different electrokinetic potentials.
- To experimentally compare electrophoretic potential of protein-coated particles with streaming potentials.
- To investigate potential discrepancies between electrophoretic and streaming potentials.
Main Methods:
- Electrophoresis of quartz particles coated with egg albumin.
- Comparison with existing streaming potential data (Briggs).
- Analysis of conditions affecting electrokinetic potential measurements.
Main Results:
- A slight, consistent difference was observed between electrophoretic and streaming potentials.
- The observed difference is likely attributable to variations in protein preparations.
- No significant real difference between electrophoretic and streaming potentials was concluded.
Conclusions:
- Conditions for comparing electrokinetic potentials were defined.
- Experimental evidence suggests protein preparation variability, not intrinsic potential differences, causes discrepancies.
- The study enhances precision in estimating electrical mobilities of microscopic particles.
Related Concept Videos
01:20Electrophoresis: Overview
Electrophoresis is a powerful analytical separation technique that relies on the differential migration of charged species when subjected to an electric field. The core strength of electrophoresis lies in its ability to separate high-molecular-weight species in complex mixtures. It has found widespread use in biochemistry, molecular biology, and analytical chemistry, allowing the separation of compounds like amino acids, nucleotides, carbohydrates, and proteins with excellent resolution.
There...
There...
01:30Capillary Electrophoresis: Applications
Capillary electrophoretic separations offer various modes, each with unique applications. These modes include capillary zone electrophoresis, capillary gel electrophoresis, capillary array electrophoresis, capillary isoelectric focusing, capillary isotachophoresis, micellar electrokinetic chromatography, and capillary electrochromatography.
Capillary zone electrophoresis (CZE) separates ionic components based on their electrophoretic mobility. It has been used to separate proteins, amino acids,...
Capillary zone electrophoresis (CZE) separates ionic components based on their electrophoretic mobility. It has been used to separate proteins, amino acids,...
01:30Processes at Electrodes
The electrode interacts with ions in the electrolyte solution at its interface. The rate of oxidation and reduction depends on the speed at which electrons can transfer through this interface. As ions attach to or leave the electrode surface, the electrode acquires a charge, and an electrical potential forms across the interface, making the process more difficult to reach equilibrium. The charge on the electrode affects the local ion concentrations in the solution, though thermal motion...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...
01:20Capillary Electrophoresis: Instrumentation
Capillary electrophoresis instrumentation typically consists of several key components. A high-voltage power supply generates the electric field necessary for the separation by connecting to an anode (the positively charged electrode) and a cathode (the negatively charged electrode) located in buffer reservoirs at each end of the capillary tube. The system includes a sample vial, a fused silica capillary tube coated with polyimide for mechanical strength through which the sample components...
02:36Electromotive Force
Electricity is generated by either electrons or ions flowing through a solution or a conducting medium. This flow of electrons or specifically electrical charge is defined as an electric current. When electrons move through a wire, they generate an electric current. It can be recalled that in a redox reaction, electrons are lost and gained. In the spontaneous redox reaction of zinc with copper, when zinc is immersed in a copper ion solution, a transfer of electrons from one substance to...