3,3',5,5'-Tetramethylbenzidine
（重定向自Tetramethylbenzidine）
![](/Images/godic/202502/15/3,3’,5,5’-Tetramethylbenzidine2448.png")
![Shows the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to 3,3',5,5'-tetramethylbenzidine diimine](/Images/godic/202502/15/3,3',5,5'-tetramethyl--1,1'-biphenyl--4,4'-diamine_oxidation.svg2449.png")
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 that forms a pale blue-green liquid in solution with ethyl acetate. TMB is degraded by sunlight and by fluorescent lights.