Ammonia Nitrogen

AMMONIA NITROGEN, the name for the nitrogen contained in the ammonia molecule. This nitrogen, in essence, does not differ from other nitrogen compounds of the ammonia type. The emergence of the term ammonia nitrogen should be explained by the practice of chemical analysis, in which this expression acquired purely technical significance. In other cases, it is necessary to differentiate the nitrogen that falls to the share of ammonia from other nitrogen, for example, amino nitrogen, nitrogen of amino acids and other compounds (example: formalin titration according to Sørensen). Such practical reasons provided the basis for the existence of the independent name ammonia nitrogen. In sanitary-hygienic practice, the determination of ammonia nitrogen finds application in the study of wastewater and, in particular, in the study of the processes of decay of protein substances, especially meat and fish; an example can be the method of Tilmans and Otto, proposed for determining the initial stage of fish decay, where it turned out that good-quality fish meat should contain no more than 30 mg NH₃ per 100 g and 0.1% of amino acid nitrogen. For details of methods for determining ammonia, see Ammonia.