Nigrosin is a mixture of synthetic black dyes (CI 50415, Solvent black 5) made by heating a mixture of nitrobenzene, aniline and aniline hydrochloride in the presence of a copper or iron catalyst. Its main industrial uses are as a colorant for lacquers and varnishes and in marker-pen inks. Sulfonation of nigrosin yields a water soluble anionic dye, nigrosin WS (CI 50420, Acid black 2).[1]

In biology, nigrosin is used for negative Staining of bacteria.[2][3] The shapes and sizes of the organisms are seen as color-free outlines against the dark background. An advantage of using this method, rather than regular positive stains like methylene blue or carbol fuchsin, is that prior fixation by heat or alcohol is not needed, so the organisms are seen in more life-like shapes. Furthermore, negative staining with nigrosin can reveal some microorganisms that cannot be stained by regular methods. Nigrosin WS is used in tests for viability: living cells exclude the dye, but it enters dead cells.[4]


  1. ^ Green FJ (1990) The Sigma-Aldrich Handbook of Dyes, Stains and Indicators, pp.513-515. Milwaukee: Aldrich. ISBN 0941633225
  2. ^ Clark G (1981) Staining Procedures Used by the Biological Stain Commission, 4th ed. p.412. Baltimore: Williams & Wilkins.
  3. ^ Green FJ (1990) The Sigma-Aldrich Handbook of Dyes, Stains and Indicators, pp.513-515.
  4. ^ Sanderson JB (1994) Biological Microtechnique. Oxford: BIOS, p.184. ISBN 1872748422

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  • Nigrosīn — Nigrosīn, s. Induline …   Meyers Großes Konversations-Lexikon

  • Nigrosin — Ni|gro|sin auch: Nig|ro|sin 〈n. 11〉 in der Leder u. Textilindustrie verwendeter blauvioletter Farbstoff [zu lat. niger „schwarz“] * * * Ni|g|ro|sin [lat. niger = schwarz; ↑ in (3)], das; s, e: Gruppenbez. für schwarze Phenazinfarbstoffe zum… …   Universal-Lexikon

  • nigrosin — ni·gro·sin (niґgro sin) an aniline dye having a special affinity for ganglion cells, used to stain tissues from the central nervous system for study under the microscope …   Medical dictionary

  • Nigrosin — Ni|gro|sin auch: Nig|ro|sin 〈n.; Gen.: s, Pl.: e; Chemie〉 blauvioletter Farbstoff, in der Leder u. Textilindustrie verwendet [Etym.: zu lat. niger »schwarz«] …   Lexikalische Deutsches Wörterbuch

  • Nigrosin — Ni|gro|sin das; s, e <zu lat. niger, Gen. nigri »schwarz« u. ↑> violetter bis blauschwarzer synthetischer Farbstoff zum Färben von Papier, Leder, Kunststoffen u. a …   Das große Fremdwörterbuch

  • nigrosin — n. blue or black dye used for dyeing leather and fabrics (Chemistry) …   English contemporary dictionary

  • nigrosin — ni·gro·sin …   English syllables

  • Nigrosin — Ni|g|ro|sin, das; s, e <lateinisch> (ein Farbstoff) …   Die deutsche Rechtschreibung

  • nigrosin — noun see nigrosine …   Useful english dictionary

  • nigrosin, nigrosine — A variable mixture of blue black aniline dyes; used as a histologic stain for nervous tissue and as a negative stain for studying bacteria and spirochetes; also used to discriminate between live and dead cells in dye exclusion staining …   Medical dictionary

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