Mercurimetric Titrations

The European and British Pharmacopoeias [2] use the mercurimetric titration assay described in Section 6.2.2 for assay of both the trihydrate and sodium salt. The method is also specified for determination of degradation products in the sodium salt monograph. 

Chloride may be determined by mercurimetric titration, spectrophotometry, couiometric-amperometric titration, or, most commonly today, ISE. 

Chloride is determined by mercurimetric titration to the sodium nitroprusside end-point. Carbonates, acetates and borates do not interfere in the titration but large amounts of ammonium salts do interfere. The method has been applied to methyltrichlorosilane, dimethyldichlorosilane, diethyldichlorosilane, phenylmethyldichlorosilane and phenyltrichlorosilane. Methods have been described76,77 based on reaction with amines for the determination of chlorine directly linked to silicon in alkyl aryl chlorosilanes. One method76 is based on the formation of aniline hydrochloride according to the equation ... 

In the mercurimetric titration of thiol compounds in proteins( the flat titration curves became steep after the addition of chloride ions. The titration can be carried out in acetate pH 5-6 buffer with 0-5 M potassium chloride, phosphate pH 7-3 buffer with 0-5 M potassium chloride or borate pH 8-8 buffer with 0-5 M ammonium nitrate. In the presence of ammonia the curves were steep, even in the absence of chlorides. It has been suggested< > that ammonia prevents the bonding of mercury to groups other than the thiol grouping. 

Method 2.1 Determination of Chlorine in Polymers Containing Chloride and Sulfur and/or Phosphorus and/or Fluorine. Oxygen Flask Combustion - Mercurimetric Titration... 

METHOD 78 - DETERMINATION OF CHLORINE IN POLYMERS CONTAINING CHLORIDE AND SULPHUR AND/OR PHOSPHORUS AND/OR FLUORINE. OXYGEN FLASK COMBUSTION - MERCURIMETRIC TITRATION. 

Determination of chlorine in polymers containing chlorine and sulphur and/or phosphorus and/or fluorine. Oxygen flask combustion - mercurimetric titration... 

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. 

The use of argentometric, mercurimetric or iodometric amperometric titration is common [3,118], The reactions of thions and disulphide groups with mercuric salts have been described [118,119]. Amperometric titration of sulphydryl groups is often applied to the analysis of proteins or body fluids and tissues, respectively [3]. In particular the papers of Benesch, and Lardy and Benesch [121,122] and of others [123-126] are to be mentioned here. 

Mercurimetric methods have no advantage over the argentimetric methods for the titration of cysteine, but they are more suitable for the determination oiglutathione The method has been used for the determination of soluble thiols in flour,... 

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