Nitrate tests

Salpeter-luft,/. nitrogen (old name), -messer, m. nitrometer, -milchsiure, /. lactic acid nitrate, -papier, n. niter paper, nitrous paper, -plantage, /. saltpeter plantation, -probe, /. saltpeter test, nitrate test saltpeter sample. 

Practice for detecting susceptibility to intergranular attack in ferritic stainless steels Method of salt spray (fog) testing Method for mercurous nitrate test for copper and copper alloys... 

Procedure. Prepare an anion exchange column (Section 7.8) using about 40g of Duolite A113 (chloride form). The ion exchange tube may be 16 cm long and about 12 mm internal diameter. Wash the column with 0.6M sodium nitrate until the effluent contains no chloride ion (silver nitrate test) and then wash with 50 mL of 0.3 M sodium nitrate. 

The older technique for this purpose (Ref 8), variously referred to as the paraffin test, the paraffin-glove test, the dermal nitrate test, and the diphenylamine test, had been abundantly shown to be unreliable, was no longer accepted in most US courts, and was now seldom used by good crime investigation laboratories... 

Thus, the dermal nitrate test is a color test for unbumed or partially burned gunpowder, ie, nitrocompds, which form a blue product with the acidic diphenylamine reagent... 

Intermittent silver nitrate tests will indicate whether the solution is free of salts. 

Note 2 In order to convert DPhA to its hexanitro-derivative, NC must be present in sample in quantity 1 g per each lOmg of DPhA. If NC is absent, use 20ml of fuming nitric acid in lieu of acid of sp gr 1.42 Note 3- Centralices, diphenylurea and diphe-nylurethane interfere with nitration test Test 2- Gravimetric Bromination Method,... 

The most reliable method of determining the quality of glycerine is the laboratory nitrating test. This should be carried out under conditions that correspond as closely as possible to those prevailing in the plant. During the laboratory nitration, temperature, the rate of separation of the nitroglycerine and the add layers, the contact surface of phases and so on should be recorded. 

Acetates may be detected by formation of foul-smelling cacodyl (poisonous) on heating with dry arsenic tiioxide. Other tests for acetate are the lanthanum nitrate test in which a blue or bluish-brown ring forms... 

BP and EP recommend that for the bromide test, a sample solution has to be first acidified with dilute nitric acid, and silver nitrate solution is added to produce a curdled, pale yellow precipitate. This precipitate will dissolve with difficulty when suspended in a solution consisting of 2 ml of water and 1.5 ml of ammonia. Unlike BP and EP, USP employs a silver nitrate test for identification of bromide. In this test, addition of silver nitrate test solution to the solution of rocuronium bromide (1 part of rocuronium bromide in 100 parts of water) will produce a white precipitate which is insoluble in nitric acid and slightly soluble in 6N ammonium hydroxide. 

Silver nitrate test The compound to be tested is treated with a few drops of 1% alcoholic silver nitrate. A white precipitate indicates a positive reaction. This could be due to either silver chloride (reaction with a reactive alkyl halide), silver alkynide (reaction with a terminal alkyne), or the silver salt of a carboxylic acid (reaction with a carboxylic acid). 

In 1922, F. Benitez recorded this technique as a method for revealing the presence of propellant particles on the hands of a firer.112 114 In Mexico in 1931, T. Gonzales performed a modified version of Iturrioz s test using molten paraffin wax on the hands of a firer and in 1933 demonstrated the test in the United States. The test has also been referred to as the dermal nitrate test, the diphenylamine test, and the Gonzales test.115,116... 

I. Castellanos, Dermo-Nitrate Test in Cuba, Journal of Criminal Law and Criminology 33, no. 6 (March/April 1953) 482. 

H. W. Turkel, and J. Lipman, Unreliability of Dermal Nitrate Test for Gunpowder, Journal Criminal Law Criminology and Police Science 46 (1955) 281. 

Since analytical results do not give a clear idea as to the usefulness of xylene for nitration, nitration tests on a laboratory scale are recommended. 

In the absence of any other criteria, a sample of each meta-cresol batch to be nitrated should be subjected to a laboratory nitration test. 

If the product contains chlorine as indicated by the alcoholic silver nitrate test, it may be purified by adding a small amount of anhydrous calcium oxide (0.5 g. per 50 g. of product) and redistilling under reduced pressure. 

Tannic acid-silver nitrate test The basis of this test is the reducing action of tannic acid (a glucoside of digallic acid) upon the silver ammine complex [Ag(NH3)2]+ to yield black silver it therefore precipitates silver in the presence of ammonia but not from a slightly acid silver nitrate solution. 

Reduction of nitrates in alkaline medium Ammonia is evolved (detected by its odour by its action upon red litmus paper and upon mercury(I) nitrate paper or by the tannic acid-silver nitrate test, Section III.38, reaction 7) when a solution of a nitrate is boiled with zinc dust or gently warmed-with aluminium powder and sodium hydroxide solution. Excellent results are obtained by the use of Devarda s alloy (45 per cent Al, 5 per cent Zn, and 50 per cent Cu). Ammonium ions must, of course, be removed by boiling the solution with sodium hydroxide solution (and, preferably, evaporating almost to dryness) before the addition of the metal. 

Attention is directed to the fact that arsenites are reduced in alkaline solution by aluminium, Devarda s alloy, etc., to arsine, which blackens mercury(I) nitrate paper and also gives a positive tannic acid-silver nitrate test. Hence neither the mercury(I) nitrate test nor the tannic acid-silver nitrate test for ammonia is applicable if arsenites are present. 

Cobalt nitrate test Phosphates when heated on charcoal and then moistened with a few drops of cobalt nitrate solution, give a blue mass of the phosphate, NaCoP04. This must not be confused with the blue mass produced with aluminium compounds (see Section III.23). 

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