|3D Ball and Stick|
|style="background: #F8EABA; text-align: center;" colspan="2" | Identifiers|
|SMILES||Script error: No such module "collapsible list".|
|style="background: #F8EABA; text-align: center;" colspan="2" | Properties|
|Molar mass||240.3482 g/mol|
|style="background: #F8EABA; text-align: center;" colspan="2" | Hazards|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)|
3,3’,5,5’-Tetramethylbenzidine or TMB is a chromogenic substrate used in staining procedures in immunohistochemistry as well as being a visualising reagent used in enzyme-linked immunosorbent assays (ELISA). TMB is a white crystal powder which forms a pale blue-green liquid in solution with ethyl acetate.
In solution, TMB forms a blue product when allowed to react with peroxidase enzymes such as horseradish peroxidase. The resulting colour change can be read on a spectrophotometer at a wavelength of 370 or 655 nm. The reaction can be halted by addition of acid or another stop reagent. Using sulphuric acid turns the product a yellow colour which may be read at 620 nm.
TMB should be kept out of direct sunlight as it is photosensitive. It is not known if TMB is carcinogenic and the evidence is contradictory: TMB is not mutagenic by the Ames test, and did not cause tumours in 24 rats (but that experiment was uncontrolled). On that evidence, it has been used as a replacement for carcinogenic compounds such as benzidine and o-phenylenediamine.
- Sigma Aldrich Catalog Entry for 3,3′,5,5′-Tetramethylbenzidine
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