General Description
Pale yellow crystals or off-white powder.
Reactivity Profile
3,3',5,5'-TETRAMETHYLBENZIDINE(54827-17-7) is sensitive to prolonged exposure to light . Neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen may be generated in combination with strong reducing agents, such as hydrides.
Air & Water Reactions
Insoluble in water.
Fire Hazard
Flash point data for this chemical are not available, however, 3,3',5,5'-TETRAMETHYLBENZIDINE is probably combustible.
Description
Tetramethylbenzidine(TMB or 54827-17-7) is a chromogenic substrate used in staining procedures in immunohistochemistry as well as being a visualising reagent used in enzyme-linked immunosorbent assays (ELISA). It is a white solid that forms a pale blue-green liquid in solution with ethyl acetate. TMB is degraded by sunlight and by fluorescent lights. It is a soluble chromogen substrate for horseradish peroxidase detection systems. Tetramethylbenzidine is recommended for ELISA procedures.
Chemical Properties
Tetramethylbenzidine is a white or light yellow solid, odorless, tasteless, insoluble in water, easily soluble in acetone, ether, dimethyl sulfoxide, dimethylformamide and other organic solvents. It forms a pale blue-green liquid in solution with ethyl acetate. TMB is degraded by sunlight and by fluorescent lights.
Uses
3,3,5,5-Tetramethyl benzidine is used as a reagent in a sensitive staining procedure for the detection of low levels of heme-associated peroxidase activity of cytochrome
P-450 on SDS-polyacrylamide or agarose gel; non-carcinogenic substitute for benzidine as reagent for the detection of blood and determination of hemoglobin content.
Application
3,3′,5,5′-Tetramethylbenzidine (TMB or 54827-17-7) is a chromogenic substrate used in staining procedures in immunohistochemistry as well as being a visualising reagent used in enzyme-linked immunosorbent assays (ELISA). The substrate produces a soluble end product that is pale blue in color and can be read spectrophotometrically at 370 or 620-650 nm. The TMB reaction may be stopped with 2 M H2SO4 (resulting in a yellow color), and read at 450 nm. A sensitive and specific reagent for the detection of blood, assay of hemoglobin, assay of peroxidases.
Preparation
Synthesis of 3,3',5,5'-Tetramethylbenzidine: Using 2,6-dimethylaniline as raw material, through activation, oxidative coupling and purification, pure 3,3,5,5-tetramethylbenzidine was obtained Methylbenzidine, the total yield is 65%.
Reactions
TMB can act as a hydrogen donor for the reduction of hydrogen peroxide to water by peroxidase enzymes such as horseradish peroxidase.
Shows the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to 3,3',5,5'-tetramethylbenzidine diimine
The resulting diimine causes the solution to take on a blue colour, and this colour change can be read on a spectrophotometer at the wavelengths of 370 and 650 nm.
Biochem/physiol Actions
3,3′,5,5′-Tetramethylbenzidine/TMB can be used as a chromogen to increase the progression of product obtained in peroxidase reaction. In food and environmental decontamination procedures, TMB can be used in in?situ free available chlorine (FAC) monitoring of chlorite-based sanitizers.
Carcinogenicity
The carcinogenic potential of Tetramethylbenzidine is uncertain due to conflicting evidence. It is not mutagenic by the Ames test, and did not induce formation of tumors in a single-arm study of 24 rats. On that evidence, it has been used as a replacement for carcinogenic compounds such as benzidine and o-phenylenediamine.
DOI:
10.1177/26.2.24068
