The chemical basis of Dyeing Agent
As a biological dye, it is necessary to meet two requirements at the same time: a bright and transparent color, and can be combined with tissue cells; Dyeing Agent dye molecules can display the color of the gene, known as the chromophore. The main chromophores are:
The main chromophore
The nitroso and azo groups show a stronger color, and there is one such chromophore in the colorant that can stain the color. Other chromophores are not the case, Dyeing Agent there must be a few chromophores, quinone molecules have four chromophores, two carbonyl 2 alkenyl.
A large number of synthetic dyes are derived from coal tar distillation, they are benzene derivatives, so the benzene ring is the basis for synthetic dyes. Benzene itself is colorless, but its hydrogen atoms are replaced by a chromophore with a color. A benzene ring compound containing a chromophore called a chromogen.
Benzene + chromophore = color
The color is not well combined with the tissue cells, Dyeing Agent even if the color is also very easy to take off. So only with the color of the color can not become a dye, the dye molecules need to have to promote the combination of stains and tissue cells genes, so that the base known as the chromophore. Such as
Amino carboxyhydroxy sulfonic acid groups
Amino groups in the solution to form cation (+), alkaline; other hydroxyl, carboxyl and sulfonic acid groups are anion (-) it is acidic. Such as trinitrotoluene is a chromogen, although it is chromophore - nitro, but the lack of help chromophore, so no staining, can not be called dyes. Dyeing Agent If a hydrogen atom in the trinitrobenzene molecule is replaced by a hydroxyl group, the resulting compound has both a chromophore and a chromophore-hydroxyl group, which is a commonly used acid dye picric acid.
It can be seen that the role of the chromophore is to make the color formation of salts, ionization in the solution can become charged ions, Dyeing Agent so as to be combined with the composition of the corresponding tissue cells.