Electrophoresis vs. Electrolysis

Difference Between Electrophoresis And Electrolysis


Electrophoresis, the movement of charged particles through a fluid in an electric field. The electrophoretic movement of these particles is used in several ways for the analysis and separation of mixtures.


The most important use of electrophoresis is in the analysis of blood proteins. Electrophoresis can be used for investigative purposes. Electrophoresis is used to study viruses and bacteria, nucleic acids, and some types of smaller molecules, including organic acids and amino acids. It is also used to analyze mixtures of complex metal ions.


Electrolysis, the decomposition of chemical compounds by an electric current. It is a widely used industrial process, particularly for the production and refining of metals. Electroplating, another important electrolytic process, is covered in a separate article.

In electrolysis the compound to be decomposed is made part of a solution or molten salt that conducts electricity and is called the electrolyte. A direct current is passed through the electrolyte between two conductors called electrodes. The electrodes are made of metal or of a nonmetallic material, such as graphite, that conducts electricity. The electrode attached to the negative terminal of the battery or power supply is called the cathode, while the one attached to the positive terminal is called the anode. Electrons enter the solution through the cathode and leave it through the anode. Reduction occurs at the cathode, oxidation at the anode.

The electrolysis of water illustrates certain aspects of the process. In order for water to be decomposed by electrolysis something must be added to it to enable it to conduct electricity. Either sulfuric acid or sodium hydroxide may be used. The sulfate ion is not oxidized at the anode, nor is the sodium ion reduced at the cathode. Only oxygen and hydrogen appear at the electrodes. In all electrolysis the electrode materials must be properly chosen so that they do not react with the electrolyte and produce unwanted side reactions. In this case the anode must be of a material, such as platinum or graphite, that is not oxidized. The electrolysis of water follows Faraday’s laws. Oxygen and hydrogen are liberated in the ratio of 1:2 by volume or 8:1 by weight, and the quantities produced can be predicted by multiplying the current in amperes by the time in seconds, then dividing by the Faraday constant, 96,500, to obtain the number of gram-equivalents of each product.


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