Toughened Silver Nitrate »Toughened Silver Nitrate contains not less than 94.5percent of AgNO3,the remainder consisting of silver chloride (AgCl). Packaging and storage— Preserve in tight,light-resistant containers. Identification— A: Asolution (1in 50)responds to the tests for Silver á191ñ. B: Mix a solution (1in 10)in a test tube with 1drop of diphenylamine TS,then carefully superimpose it upon sulfuric acid:a deep blue color appears at the zone of contact. Copper— Asolution (1in 10)shows no trace of blue coloration when treated with an excess of 6Nammonium hydroxide. Assay— Add about 700mg of Toughened Silver Nitrate,accurately weighed,to 50mLof water,and when the silver nitrate has dissolved,filter the solution.Thoroughly wash the filter and sediment with water,add 2mLof nitric acid and 2mLof ferric ammonium sulfate TSto the combined filtrate and washings,and titrate with 0.1Nammonium thiocyanate VS.Each mLof 0.1Nammonium thiocyanate is equivalent to 16.99mg of AgNO3. Auxiliary Information— Staff Liaison:Behnam Davani,Ph.D.,MBA,Senior Scientist Expert Committee:(PA7)Pharmaceutical Analysis 7 USP28–NF23Page 1768 Phone Number:1-301-816-8394