Ethyl Green

Property Data Common name Suggested name Other names C.I. number C.I. name Class Ionisation Solubility aqueous Solubility ethanol Absorption maximum Colour Empirical formula Formula weight   Ethyl green Ethyl green Methyl green 42590 – Triarylmethane Basic Soluble – 629, 423 (Aldrich) Green C27H35N3ClBr 517 (Conn) 472.5 (Aldrich)

Ethyl green is made from crystal violet by the addition of an ethyl group. Like methyl green, which has a methyl group as the seventh group, crystal violet is common as a contaminant. If it is important to ensure there is no crystal violet present, the solution of ethyl green may be washed with chloroform to extract the crystal violet. Ethyl green may be used whenever methyl green is specified, and appears to indistinguishable from it. The difference in the formula weights probably derives from Conn giving the chloride and bromine salt, and Aldrich giving the zinc chloride salt.

The Merck Index and Aldrich give the name methyl green for this dye. Most histotechnologists know the closely related dye, CI 42585 as methyl green and this dye as ethyl green. The two dyes are very similar, and are probably interchangeable. It has been suggested that ethyl green is often the dye actually provided when methyl green is purchased.

 

Reference
R. D. Lillie.
Conn's Biological Stains
Williams & Wilkins, Baltimore, MD., U.S.A.

Aldrich chemical catalogue, 1992
Aldrich Chemical Company, Milwaukee, WI, USA.

Susan Budavari, Editor, (1996)
The Merck Index, Ed. 12
Merck & Co., Inc., Whitehouse Station, NJ, USA