Amido black

Amido black

Amido Black 10B is an amino acid staining azo dye used in biochemical research to stain proteins in acrylamide gels, and on cellulose membranes in Western blot analysis. It is a versatile stain that can also be used in the detection of blood on materials in forensic science due to its high sensitivity for proteins. The dye binds to proteins by a process known as adsorption, making it useful for visualizing proteins that have been separated by electrophoresis.

Properties

Amido Black 10B is a dark blue or black powder that is soluble in water, ethanol, and acetic acid. Its molecular formula is C₂₂H₁₄N₆Na₂O₉S₂, and it has a molecular weight of 616.48 g/mol. The dye has a maximum absorption spectrum at approximately 618 nm when dissolved in water.

Applications

Protein Staining

In the laboratory, Amido Black 10B is primarily used for staining proteins in acrylamide gels after polyacrylamide gel electrophoresis (PAGE) and on cellulose membranes after Western blotting. The staining process involves fixing the proteins in the gel or on the membrane with a solution, typically containing acetic acid and methanol, followed by staining with Amido Black 10B solution. After staining, the gel or membrane is destained using a solution similar to the fixing solution, which removes the dye from areas not occupied by proteins, thereby allowing the visualization of protein bands.

Forensic Science

In forensic science, Amido Black 10B is used for the enhancement of blood fingerprints on porous surfaces. The dye has a high affinity for the protein components of blood, making it an effective tool for visualizing blood patterns and fingerprints that would otherwise be invisible. This application is particularly useful in crime scene investigations, where the detection and analysis of blood evidence can provide critical information.

Staining Protocol

A typical staining protocol with Amido Black 10B involves several steps: 1. Fixation of the protein sample in the gel or on the membrane with a solution containing acetic acid and methanol. 2. Staining with a solution of Amido Black 10B, often prepared in a mixture of water, ethanol, and acetic acid. 3. Destaining with the same solution used for fixation, which removes excess dye without removing the dye bound to proteins. 4. Visualization of the stained proteins under natural light or using a gel documentation system.

Safety and Handling

Amido Black 10B, like many azo dyes, should be handled with care. It is advisable to wear protective clothing, gloves, and eye protection when working with this chemical. Waste disposal should be conducted in accordance with local regulations to minimize environmental impact.