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Key Documents

114510

Sigma-Aldrich

Methyl Orange

ACS reagent, Dye content 85 %

Synonym(s):

4-[4-(Dimethylamino)phenylazo]benzenesulfonic acid sodium salt, Acid Orange 52, Helianthin, Orange III

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About This Item

Empirical Formula (Hill Notation):
C14H14N3NaO3S
CAS Number:
Molecular Weight:
327.33
Colour Index Number:
13025
Beilstein:
4732884
EC Number:
MDL number:
UNSPSC Code:
12171500
PubChem Substance ID:
NACRES:
NA.47

grade

ACS reagent

Quality Level

form

powder

composition

Dye content, 85%

technique(s)

titration: suitable

color

orange

pH

3.0-4.4, pink to yellow

visual transition interval

3.2-4.4, red to yellow

mp

>300 °C

λmax

505 nm

application(s)

diagnostic assay manufacturing
hematology
histology

storage temp.

room temp

SMILES string

[Na+].CN(C)c1ccc(cc1)\N=N\c2ccc(cc2)S([O-])(=O)=O

InChI

1S/C14H15N3O3S.Na/c1-17(2)13-7-3-11(4-8-13)15-16-12-5-9-14(10-6-12)21(18,19)20;/h3-10H,1-2H3,(H,18,19,20);/q;+1/p-1/b16-15+;

InChI key

STZCRXQWRGQSJD-GEEYTBSJSA-M

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General description

Methyl orange (C.I. 13025) is the sodium salt of p-dimethylaminoazobenzenesulfonic acid.It is an orange-colored synthetic dye, which changes color depending on the pH of the solution. It develops a red color in acidic solution and yellow color in basic solution.

Application

Methyl orange is used as a-
  • pH indicator in the cell sap
  • counterstain to crystal violet in staining pollen tubes
  • component of a polychrome histological stain
  • solution indicator, such as in assays of oxalic and malonic acids
  • in other biomedical applications that include use in film dosimeters and as a reagent for the assay of bromide ions.

Biochem/physiol Actions

Methyl Orange is an azo dye which works as a pH indicator.

Pictograms

Skull and crossbones

Signal Word

Danger

Hazard Statements

Precautionary Statements

Hazard Classifications

Acute Tox. 3 Oral

Storage Class Code

6.1C - Combustible acute toxic Cat.3 / toxic compounds or compounds which causing chronic effects

WGK

WGK 3

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

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Characterization of methyl orange and its photocatalytic degradation products by HPLC/UV?VIS diode array and atmospheric pressure ionization quadrupole ion trap mass spectrometry.
Baiocchi C, et al.
International Journal of Mass Spectrometry, 214, 247-256 (2002)
Somayeh Mirsadeghi et al.
Journal of environmental management, 270, 110831-110831 (2020-06-09)
A simple biogenic approach for synthesis of Fe3O4/Au nanocomposite with 31 nm size using aqueous extract of Carum carvi L. seeds has been reported. Phytochemicals of Carum carvi L. seeds extract play three roles, including reducing, capping, and stabilizing agents during
Encapsulation of methyl orange pH-indicator into a sol-gel matrix.
Zaggout FR, et al.
Materials Letters, 59, 2928-2931 (2005)
Yu Lim Chen et al.
Optics express, 21(6), 7240-7249 (2013-04-03)
A low-cost and efficient photocatalytic reactor for environmental treatment and green technology was presented. ZnO nanorods firmly growing on polycarbonate optical disk substrate are generally perpendicular to the substrate as the immobilized photocatalyst of the spinning disk reactor. The photocatalytic
Dong-Min Yun et al.
Water research, 47(5), 1858-1866 (2013-02-05)
Here, we demonstrated that nano zero-valent iron (nZVI) impregnated onto self-organized TiO(2) nanotube thin films exhibits both oxidation and reduction capacities in addition to the possible electron transfer from TiO(2) to nZVI. The TiO(2) nanotubes were synthesized by anodization of

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