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Methyl Blue

for microscopy (Bot., Hist.), indicator (pH 9.4-14.0)

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Acid blue 93, Aniline blue water soluble, Cotton blue, Poirriers blue, Water blue
Empirical Formula (Hill Notation):
CAS Number:
Molecular Weight:
Colour Index Number:
EC Number:
MDL number:
PubChem Substance ID:


for microscopy (Bot., Hist.)
indicator (pH 9.4-14.0)

Quality Level


powder or crystals




water: 0.01 g/10 mL, blue to very deep blue


≥200 at 310-320 nm
≥400 at 595-605 nm


diagnostic assay manufacturing

storage temp.

room temp

SMILES string




InChI key


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General description

Methyl Blue (C.l. 42780) is a triaminotriphenylmethane dye with each amino group carrying a monosulfonated phenyl substituent. It is also known as Water blue, Acid blue 93, Cotton blue, Poirriers blue, and Aniline blue water soluble.


Methyl Blue has been used:
  • to stain leaf disks for callose visualization within the cells
  • to incubate cells for 4′,6-diamidino-2-phenylindole (DAPI)/septa staining
  • as a marker for β-(1-3)-d-glucans or acidic phloroglucinol for the detection of callose and lignin
  • in Mann′s stain as it involves a methyl blue-eosin mixture

Storage Class Code

13 - Non Combustible Solids



Flash Point(F)

572.0 °F - Pensky-Martens closed cup

Flash Point(C)

> 300 °C - Pensky-Martens closed cup

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Juan Guo et al.
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A Arunarani et al.
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Basic Violet 3 and Acid Blue 93 are the most important group of synthetic colourants extensively used in textile industries for dyeing cotton, wool, silk and nylon. Release of these dye pollutants in to the environment adversely affects the human
Lijun Dong et al.
Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy, 66(4-5), 1317-1322 (2007-02-06)
A novel flow injection method with resonance light scattering detection was developed for the determination of total protein concentrations. This method is based on the enhancement of RLS signals from Methyl Blue (MB) by protein. The enhanced RLS intensities at
Xiaoli Hou et al.
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A new synchronous fluorescence scan analysis was developed for the determination of HSA with high sensitivity with a triphenylmethane acid dye methyl blue as a fluorescence probe. When Deltalambda=140 nm, the synchronous fluorescence peak of methyl blue is located at

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