B 1377 (OTTO) Bathocuproinedisulphonic acid disodium salt, GR - used as a stain for proteins in polyacrylamide gels. Bathocuproinedisulphonic acid disodium salt, GR - used as a reagent for the determination of copper. It acts as an exciton blocking barrier which prohibits excitons diffusion process towards the Al electrode otherwise being quenched.