An accelerated microdiffusion Instltuufv . . - ' ^ - 1 "̂ ?̂ " . ' method for the determination of ammonia in cartilaginous fish By W . VYNCKE

NE X T to trimethylamine, ammonia is the most typical spoilage product in fish, molluscs and crustaceans. I t is generally determined together with other volatile nitrogen bases, as total volatile basic nitrogen (TVB). The objective quality determinations of cartilaginous fish such as dogfish and skate, however, raises special problems. These fish contain large quantities of urea (1.5 to 2 per cent.) present in all parts of the body (muscles, intestines, blood, slime, etc.)^ By the action of a bacterial enzyme, the urease, urea is relatively quickly degraded to ammonia and carbon dioxide.