Silver nitrate, argentimetric titrations

These are titrations in which the analyte and titrant react to form a precipitate. The only common titrant used is silver nitrate (argentimetric titrations), and its use is mainly restricted to the determination of... 

Soliman and Belal investigated argentimetric (67,68) and mercurimetric (69) methods. Hydralazine precipitates silver from ammoniacal silver nitrate solution. The silver is dissolved with hot nitric acid and titrated with ammonium thiocyanate solution. Alternatively, mercury is precipitated from alkaline potassium mercuric iodide solution. The precipitated mercury is dissolved by adding excess standard iodine solution. The excess iodine is back-titrated with sodium thiosulfate solution after acidifying with acetic acid. 

Issa et al. [9] used various metal ions for the volumetric determination of mefenamic acid. Mefenamic acid was precipitated from its neutral alcoholic solution by a standard solution of either silver nitrate, mercurous acetate, or potassium aluminum sulfate. In the argentimetric procedure, residual Ag(I) was titrated with standard NH4SCN. With Hg(OAc)2 or potash alum, the residual metal was determined by adding EDTA and conducting back titration of excess of EDTA with standard Pb(N03)2 using xylenol orange indicator. The applied methods were used for the determination in bulk drug substance, and in its formulations. 

Precipitation is the term used to describe the process whereby a substance leaves solution rapidly, forming either a crystalline solid or amorphous solid (the precipitate). In the case of a precipitation titration, this process occurs when the analyte forms a precipitate with the titrant. The most common types of precipitation titrations use silver nitrate as the titrant. They are often referred to as argentimetric titrations. 

The other, very popular argentimetric titration the Volhard method uses different approach. An excess of the silver chloride forming silver nitrate reagent is added to the sample and after the reaction... 

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