Indulin Dyes

INDULIN DYES (Indulin, Echt-blau, Solidblau), dark blue or dark brown powders, insoluble in water, soluble with a blue color in alcohol; similar to safranines; obtained by the action of aniline on hydrochloric acid amidobenzol. When acting on nitrobenzene or nitrophenol, nigrosines are obtained. The simplest indulin has the following structure: /CH/\/\ C6H5NH2. Sulfurization of water-insoluble indulins transforms them into water-soluble indulin (Indulin NN, N, 5R, 6B, R, Echtblau C, Indaminblau). In microtechnique, the latter are specifically applicable: a) aqueous solutions: concentrated aqueous solution is diluted with water 1:6; stain for 5-20 minutes (Calberla); b) alum solutions: indulin 1.0 + ammonium alum 10.0 + water 100.0 (Rawitz); c) glycerin solutions: indulin, eosin, and aurantia (2.0 each) are triturated with 30.0 cm³ glycerin. The mixture matures for 10-12 days at 60° (Ehrlich). Mixtures a and b are used for staining sections, mixture c-for blood smears (stain for 24 hours at 37°, rinse with water, dry; results: nuclei-black, α-grains-yellow, β-grains-red, γ-grains-gray-black, erythrocytes-yellow).