Methylene green

Chemical properties

black powder

Definition

ChEBI: An organic chloride salt having 3,7-bis(dimethylamino)-4-nitrophenothiazin-5-ium as the counterion. It stains nuclei green and is sometimes used as a counterstain to red or purple primary stains.

Preparation

commonly known as Methylene Green. (C.I.Basic Blue 9, C.I. 52015) in the first use of hydrochloric acid sodium nitrite processing, and then treated with nitric acid and zinc chloride double salt precipitation..

Purification Methods

Crystallise the dye three times from water (18mL/g). [Beilstein 27 H 399.] The ZnCl2 double salt [6722-15-2] M 866.0 has the same CI.[Beilstein 27 III/IV 5157.]

Properties and Applications

dark blue light green. Soluble in water for green light blue, slightly soluble in ethanol for green light blue. In the dark for the strong sulfuric acid, diluted for green light blue. Dye with sodium hydroxide solution for purple, have violet black precipitation.