2-bromo-1-naphthol--a novel chromogen for the immunoperoxidase technique in immunohistochemistry.

2-bromo-1-naphthol is a new chromogen for the immunoperoxidase reaction in immunodot assays on nitrocellulose filters and on Western blots and could now also be employed in immunohistochemistry at the light microscopic level. It displays a blue-violet reaction product which is insoluble in aqueous solutions and almost insensitive to light. By means of this substrate for the peroxidase reaction in conjunction with 3,3'-diaminobenzidine it is also possible to perform double labellings.