Methyl Red

Methyl Red structural formula

CAS Number 493-52-7
Molecular Formula C15H15N3O2
Molecular Weight 269.304 g/mol
LogP 3.83
  • Methyl red
  • 2-{(E)-[4-(Dimethylamino)phenyl]diazenyl}benzoic acid
  • Benzoic acid, 2-[(E)-2-[4-(dimethylamino)phenyl]diazenyl]-
  • 493-52-7
  • Benzoic acid, 2-[[4-(dimethylamino)phenyl]azo]-
  • 2-(4-Dimethylaminophenylazo)benzoesaeure
  • 2-(4-dimethylaminophenylazo)benzoic acid
  • 2-[(p-Dimethylamino)phenyl]azobenzoic acid
  • 2-[[4-(Dimethylamino)phenyl]azo]benzoic acid
  • 2-Carboxy-4'-(dimethylamino)azobenzene
  • 4-(2-Carboxyphenylazo)-N,N-dimethylaniline
  • 4'-(Dimethylamino)azobenzene-2-carboxylic acid
  • Acide 2-(4-dimethylaminophenylazo)benzoique
  • acido 2-(4-dimetilaminofenilazo)benzoico
  • Benzoic acid, 2-[2-[4-(dimethylamino)phenyl]diazenyl]-
  • C.I. acid red 002
  • C.I. Acid Red 2
  • Methyl red C.I. 13020
  • NSC 215212
  • NSC 34729
  • NSC 9597
  • o-[[p-(Dimethylamino)phenyl]azo]benzoic acid
  • o-Methyl red
  • p-(Dimethylamino)azobenzene-o-carboxylic acid
  • Benzoic acid, o-((p-(dimethylamino)phenyl)azo)-
  • Benzoic acid, 2-((4-dimethylamino)phenylazo)-
  • CI Acid Red 2
  • Dimethylaminoazobenzene-2-carboxylic acid
  • 2-((4-Dimethylamino)phenylazo)benzoic acid
  • EINECS 207-776-1
  • Cerven kysela 2
  • Cerven methylova
  • UNII-69083AX1ZX
  • 4'-(Dimethylamino)azobenzene-2-carboxylic acid
  • 4'-Dimethylaminoazobenzene-2-carboxylic acid
  • 4-Dimethylamino-2'-carboxylazobenzene
  • o-((p-(Dimethylamino)phenyl)azo)benzoic acid
  • p-(Dimethylamino)azobenzene-o-carboxylic acid


HPLC Dye Separation on SHARC1 Column


Column Sharc 1, 3.2x100 mm, 3 µm, 100A
Mobile Phase MeCN/EtOH - 99/1%
Buffer H2SO4 - 0.5%
Flow Rate 1.5 ml/min
Detection UV, 500, 650 nm


Class of Compounds Dye, Hydrophilic, Ionizable
Analyzing Compounds Methyl Red, Methyl Orange, Methylene Blue, Nile Blue A

Application Analytes:

Methyl Orange
Methyl Red
Methylene Blue
Nile Blue A

HPLC Method for Analysis of Dyes
HPLC Separation of Dyes

3-Aminoacridine is an aminoacridine. Alizarin a red pigment that comes as a red powder with a slight orange tint. When dissolved it appears bright red with a slight pink undertone. Alizarin is also known as Mordant Red 11 or Turkey Red. Eosin Y is a pigment that comes as an orange powder that when dissolved in water turns bright orange. Eosin is a fluorescent staining agent. It is used to stain red blood cells, proteins on cytoplasm, collage, and muscle fibers. It is also fluorescence. Fluorescein is a dye that comes in a dark orange powder and is used as a tracer and an indicator. As it says in the name, it is also Fluorescent, obtaining a green-yellow color when under black light. Methyl red an indicator that turns red in acidic solutions (below 4.4 pH), is a shade of orange between 4.5 and 6.1 pH, and turns bright yellow in basic solutions (above pH 6.2). Nile blue, also known as Nile blue A, is used as a stain used in biology and histology as well as a pH indicator. In pH below 7 it becomes lighter shades of glue, and at pH 0 becomes almost completely translucent. At pH of seven it has a dark blue shade, while at pH higher than that it starts becoming more red. Pararosaniline Hydrochloride, also known as Basic Red 9, or C.I. 42500. It is a a magenta solid that is used as a dye. Patent Blue Violet, also known as Patent Blue, is a deep blue pigment that is often used to dye clothes. Resazurin is a blue dye as well as a pH indicator. At pH 3.8 or lower, it is bright orange, but the higher the pH the more blue it becomes, the color stops changing at the pH of 6.5 where it becomes indigo. Newcrom R1, a column that takes advantage of the newest technologies, does not contain embedded acidic nor basic ionizable groups and can retain dyes. The method is UV compatible and can be used as a general approach for analyzing similar compounds.

Application Analytes:

Eosin Y
Methyl Red
Nile Blue A
Pararosaniline Hydrochloride
Patent Blue Violet (Patent Blue)