ABSTRACT
This chapter concerns the chemical groups of dyes used in biology. The formal chemical names of most dyes are so long that they are never used in conversation or writing. Instead, each dye has one or more informal or trivial names. Many words in the informal names of dyes end in –ine or –in, and these endings have often been used wrongly, especially for microscopical stains. Chemical structures determine the colors, properties and uses of dyes, and provide the only rational basis of a classification of these compounds. The numbering system and arrangement of dyes used in the Colour Index and in Conn’s Biological Stains are based primarily on the chemical structures of chromophores. The most common substituents on the rings, which determine the properties of the dyes, are amine and hydroxyl groups. The azine chromophore contains the skeleton of phenazine, which consists of two benzene rings linked by two nitrogen atoms.
