Physiology of Finfish and Shellfish (2+1)

Principle

In a weakly alkaline solution, NH₃ reacts with hypochlorite to form monochloramine,which in the presence of phenol, catalytic amount of nitropruside ions and an excess of hypochlorite yields in dophenols. The reaction leading to this coloured complex is not yet fully understood. Probably aquinone chlorimide maybe formed in the intermediate step.