Determination of submicro quantities of ammonia

✍ Scribed by Alexander Levitzki

• Book ID: 102629511
• Publisher: Elsevier Science
• Year: 1970
• Tongue: English
• Weight: 295 KB
• Volume: 33
• Category: Article
• ISSN: 0003-2697
• DOI: 10.1016/0003-2697(70)90304-0

✦ Synopsis

All of the present methods for ammonia determination require the existen,ce of pure NH, in the assay solution. Distillation of NH, into acid is, therefore, a prerequisite (1) for the analysis of ammonia in the presence of proteins and amino acids. The distilled ammonia is then determined either titrimetrically

(2-7) or calorimetrically (8-10). The effective range of both types of methods is in the range of 0.1-1.0 pmole NH, per assay.

In this communication a new method is developed that is capable of determining NH, down to 1O-5 M (0.01 PmoleJml assay) in the presence of other nitrogenous compounds such as proteins and amino acids. Thus, no predistillation of the NH, is necessary. Beef liver GDH" catalyzes the reaction: cu-ketoglutarate f NH, + NADH + L(f)-glutamic acid + NAD (1)