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Electrophoresis Articles

Buffer Additives-Reducing Agents

By National Diagnostics | August 12, 2011 | Comments Off on Buffer Additives-Reducing Agents

Disulfide bonds between or within sample protein molecules can lead to the formation of aggregates as well as play a role in the binding of the subunits of many proteins. It is usually desirable to…

Buffer Additives-Surfactants

By National Diagnostics | August 12, 2011 | Comments Off on Buffer Additives-Surfactants

A crucial initial step in the electrophoretic separation of proteins is the solubilization of the sample molecules. This is especially true if there are extensive nonpolar interactions. Although urea in high concentration was often employed…

Buffer Additives-Hydrogen Bonding Agents

By National Diagnostics | August 12, 2011 | Comments Off on Buffer Additives-Hydrogen Bonding Agents

In most forms of electrophoresis, the solution perfusing the gel matrix typically contains one or more substances in addition to the buffer salts. Serving the purpose of modifying the properties of sample molecules, these additives…

Isotachophoresis

By National Diagnostics | August 12, 2011 | Comments Off on Isotachophoresis

Isotachophoresis is a method of electrophoresis that employs the basic principles of the stacking gel phase of multiphasic systems discussed in the preceding section. Employing nonsieving media, often low percentage polyacrylamide, isotachophoresis in its simplest…

Multiphasic Buffer Systems

By National Diagnostics | August 12, 2011 | Comments Off on Multiphasic Buffer Systems

Employing gel and buffer discontinuities to produce sharp separation among sample components, multiphasic electrophoresis design can improve the resolution of electrophoresis (especially protein electrophoresis). The system employs a separating gel in which the sample is…

Homogeneous Buffer Systems

By National Diagnostics | August 12, 2011 | Comments Off on Homogeneous Buffer Systems

In a homogeneous buffer system, the identity and concentration of buffer components are the same in the gel and the tanks. Most forms of DNA and RNA electrophoresis generally use homogeneous buffer systems. Electrophoresis of…

Electrophoresis Buffers-Choosing the Right Buffer

By National Diagnostics | August 12, 2011 | Comments Off on Electrophoresis Buffers-Choosing the Right Buffer

Several factors to consider when choosing a buffer include: 1) pKa value – A buffer should be chosen with a pKa that is very close to the desired pH, preferably within a half point. The…

The Polyacrylamide Matrix-Buffer Strength

By National Diagnostics | August 12, 2011 | Comments Off on The Polyacrylamide Matrix-Buffer Strength

The buffer system in electrophoresis controls the pH of the gel, preventing damage to sample molecules and, in certain cases, controlling the ionization state of the molecules. A second, though no less significant function, derives…

Electrophoresis Buffers–The Henderson-Hasselbalch Equation

By National Diagnostics | August 12, 2011 | Comments Off on Electrophoresis Buffers–The Henderson-Hasselbalch Equation

In its simplest form, a buffered solution contains a mixture of a weak acid and its conjugate base. The position of acid/base equilibrium is represented by the acid dissociation constant, Ka. This number is large…

The Agarose Matrix

By National Diagnostics | August 12, 2011 | Comments Off on The Agarose Matrix

A natural colloid extracted from seaweed, agarose is a linear polysaccharide made up of the repeating unit agarobiose, which consists of alternating units of 1,3-linked b-D-galactopyranose and 1,4-linked 3,6-anhydro-a-L-galactopyranose. Gels prepared from agarose have a…