Nitrate test to 2.5 micrograms and a concentration of 1 in 25,000 parts. Devarda's alloy (Copper/Aluminium/Zinc) is a reducing agent. When reacted with nitrate in sodium hydroxide solution, ammonia is liberated. The ammonia formed may be detected by its characteristic odor, and by damp red litmus paper's turning blue, signalling that it is an alkali — very few gases other than ammonia evolved from wet chemistry are alkaline. Aluminium is the reducing agent in this reaction that will occur. Diphenylamine may be used as a wet chemical test for the presence of the nitrate ion. In this test, a solution of diphenylamine
Griess test The reagent should not be stored more than three months. Griess test The Griess test is an analytical chemistry test which detects the presence of nitrite ion in solution. One of its most important uses is the determination of nitrite in drinking water. The test has also been widely used for the detection of trace explosives containing nitro groups. It is usually necessary to release the nitrite ion from the organic explosive before analysis. This is normally done by alkaline hydrolysis. The "Griess diazotization reaction" on which the Griess reagent relies was first described in 1858 by Peter Griess. Nitrite