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Crystal violet or gentian violet, also known as methyl violet 10B or hexamethyl pararosaniline chloride, is a triarylmethane dye used as a histological stain and in Gram's method of classifying bacteria. Crystal violet has antibacterial, antifungal, and anthelmintic properties and was formerly important as a topical antiseptic.
It is known in medicine as Gentian violet (or crystal violet or pyoctanin(e) [1]) and is the active ingredient in a Gram stain, used to classify bacteria. It is used as a pH indicator, with a range between 0 and 1.6. The protonated form (found in acidic conditions) is yellow, turning blue-violet above pH levels of 1.6. [4]
Crystal violet stains both Gram positive and Gram negative organisms. Treatment with alcohol removes the crystal violet colour from gram negative organisms only. Safranin as counterstain is used to colour the gram negative organisms that got decolorised by alcohol. While ex vivo, many cells continue to live and metabolize until they are "fixed".
(The others are rosaniline, new fuchsine and magenta II.) [2] It is structurally related to other triarylmethane dyes called methyl violets including crystal violet, which feature methyl groups on nitrogen. It is prepared by the condensation of aniline and para-aminobenzaldehyde. Alternatively, it arises from the oxidation of 4,4'-bis ...
Azo violet (Magneson I; [1] p-nitrobenzeneazoresorcinol) is an azo compound with the chemical formula C 12 H 9 N 3 O 4. It is used commercially as a violet dye and experimentally as a pH indicator, appearing yellow below pH 11, and violet above pH 13. [2] It also turns deep blue in the presence of magnesium salt in a slightly alkaline, or basic ...
In hemocytometry, Türk's solution (or Türk's fluid) is a hematological stain (either crystal violet or aqueous methylene blue) prepared in 99% acetic acid (glacial) [1] and distilled water. The solution destroys the red blood cells and platelets within a blood sample (acetic acid being the main lyzing agent ), and stains the nuclei of the ...
Bromocresol purple (BCP) or 5′,5″-dibromo-o-cresolsulfophthalein, is a dye of the triphenylmethane family (triarylmethane dyes) and a pH indicator. It is colored yellow below pH 5.2, and violet above pH 6.8. In its cyclic sulfonate ester form, it has a pK a value of 6.3, and is usually prepared as a 0.04% aqueous solution. [1]
Triarylmethane dyes can be grouped into families according to the nature of the substituents on the aryl groups. In some cases, the anions associated with the cationic dyes (say crystal violet) vary even though the name of the dye does not. Often it is shown as chloride.