Dermal nitrate test

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... 

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... 

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

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