Tetramethylbenzidine



Tetramethylbenzidine is used as a chromogen in detection systems based on the peroxidase and pseudoperoxidase reactions. In fact, in the presence of a suitable catalyst (peroxidase, complex-bound iron of haemoglobin or myoglobin), colourless tetramethylbenzidine is oxidised with hydrogen peroxide (or other hydroperoxide, e.g. cumene hydroperoxide) to benzidine blue: