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Fundamentals of Liquid Scintillation Counting ARTICLES

Sample Prep for Denaturing PAGE of DNA

By National Diagnostics | August 15, 2011 | Comments Off on Sample Prep for Denaturing PAGE of DNA

DNA samples for denaturing gel electrophoresis must be denatured prior to loading, to avoid time dependent denaturation artifacts on the gel. This is usually carried out by diluting the sample into 95% formamide and heating…

Denaturing Polyacrylamide Gel Electrophoresis of DNA & RNA

By National Diagnostics | August 15, 2011 | Comments Off on Denaturing Polyacrylamide Gel Electrophoresis of DNA & RNA

The electrophoretic analysis of single-stranded nucleic acids is complicated by the secondary structures assumed by these molecules. Separation on the basis of molecular weight requires the inclusion of denaturing agents which unfold the DNA or…

Horizontal and Vertical Gel Systems – Vertical Tube Gels

By National Diagnostics | August 15, 2011 | Comments Off on Horizontal and Vertical Gel Systems – Vertical Tube Gels

Tube gels were used frequently in the development of gel electrophoresis. Although they are still used for some applications (most notably for isoelectric focusing as part of 2D electrophoresis), tube gels have been superseded by…

Horizontal and Vertical Gel Systems – The Vertical Slab Gel System

By National Diagnostics | August 15, 2011 | Comments Off on Horizontal and Vertical Gel Systems – The Vertical Slab Gel System

A typical vertical apparatus used for sequencing is shown in the figure below. This system shows the components common to all vertical slab systems. The gel is cast between two glass plates, separated by spacers,…

Horizontal and Vertical Gel Systems – The Horizontal Gel System

By National Diagnostics | August 15, 2011 | Comments Off on Horizontal and Vertical Gel Systems – The Horizontal Gel System

A gel electrophoresis apparatus must allow the researcher to maintain a uniform electric field across the gel, provide cooling to prevent thermal artifacts, and allow access to the gel for sample loading and monitoring the…

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…