Fuchsine or rosaniline hydrochloride is a magenta dye with chemical formula C20H19N3·HCl. "Basic chemical data". Discovery Series online database, Developmental Therapeutics Program, U.S. National Institutes of Health. Retrieved on 2007-10-08.Goyal, S.K. "Use of rosaniline hydrochloride dye for atmospheric SO2 determination and method sensitivity analysis". Journal of Environmental Monitoring, 3, 666-670, DOI: 10.1039/b106209n. Retrieved on 2007-10-08. There are other similar chemical form… (More on Fuchsin)