Analysis of Azides for Assay, and in Complex Media

Azides must also be analyzed for trace-metal content, such as copper, mercury, or thallium, because of the possibility of enhanced sensitivity. Other tests include analysis for grit, average particle size, and crystal morphology in confor- 

This chapter emphasizes the methods of analysis for azides in current use and the applicability, simplicity, accuracy, and precision of the methods. The information is practical in nature, with the physical and inorganic chemistry held to a minimum. 

The analysis of azides was reviewed by Blay [1, 2] and Fedoroff eZ a/. [3]. Useful analytical guides include the specifications issued by governments for the purchase of military-grade azides for example in the United States. U.S. Military Specification, PA-PD 2825. February 5, 1966, or in Great Britain, Admiralty Specifications, A-163-J, Ministry of Supply, Chemical Inspectorate, Method 

The analyst has little choice in the selection of a redox analytical method. In acid solution ceric ion is the most effective oxidant however, in acid solution there is possibility of analytical error because of the volatility ofhydrazoic acid. In alkaline solution, reduction of the azide ion by homogeneous or heterogeneous reduction methods results in variable stoichiometry and cannot be used. The argentometric determination of azide ion in neutral solution is satisfactory but has one serious drawback the manipulation of silver azide, a high cxplosix c. Two basic approaches have evolved for the assay of azide ion  

Precipitation of silver azide from acetate solution and gravimetric determination of the silver as silver azide or silver chloride, or volumetrically by addition of an excess of standard silver nitrate solution and back-titration with standard ammonium thiocyanate using ferric alum as internal indicator. 

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