3-(1-(4-Amino-3-methyl-5-sulfonatophenyl)-1-(4-amino-3-sulfonatophenyl)methylen)cyclohexa-1,4-diensulfonsaeure

BeschreibungFuchsin acid (Acid magenta) is a red, acid dye of the triphenylmethane series, consisting of the sodium salts of the sulphonic acids of basic fuchsin or of the individual dyes (pararosaniline, rosaniline and new fuchsin), of which the latter is a mixture. The composition of fuchsin acid, like fuchsin basic, can vary with the country of origin and from one manufacturer to another. Industrial uses of the dye include the colouring of crepe tissues, soap and photographic films and the dyeing of leather, which it penetrates easily. A 1 % solution of Microme No. 5 in deionized or distilled water (previously adjusted to pH 7-0 with alkali) has a pH of 5-0. Fuchsin acid is decolorized in solution by the addition of NaOH and in this form it is used as an indicator (known as Andrade's indicator) : this finds application in bacteriology for detecting acid-forming organisms. Very dilute aqueous solutions of the dye in London tap water (pH about 8-1) fade within two or three seconds. In deionized water they retain their colour considerably longer, however.

VerwendenAs pH indicator; biological stain.