Copper-Mediated Non-Enzymatic Formation of Nitrite from Ammonia and Hydrogen peroxide at Alkaline pH

Ammonia is quantitatively oxidized by hydrogen peroxide to form nitrite, 7.63 ± 0.14 nmoles μmole H2O2. The reaction is accomplished within a minute occurring both at 4 and 20 C (P>0.1, n = 5). The reaction is mediated by copper (II) as it fails to occur in absence of copper; and is quantitatively reduced in presence of copper sequestering agents. The reaction requires the presence of free ammonia as it fails to occur at acidic and neutral pH or when ammonia is substituted with equivalent molar mass of ammonium chloride. Formation of cuprous oxide is presumably the primary step to facilitate the generation of nitrite since copper reduction has been quantitatively linked to nitrite formation. The study provides an alternative method for nitrite generation from oxidation of ammonia by hydrogen peroxide mediated by copper.