ABSTRACT
A rapid, accurate and reproducible method for the potentiometric determination of captopril in aqueous solution, is described. The method is based on the reaction of the thiol and the carboxylic group of captopril with silver ions whereby an equivalent amount of the acid is liberated; thereafter, the amount of captopril is determined by the potentiometric titration with sodium hydroxide. This method can be applied also for direct determination of captopril content in tablets.
Subject(s)
Captopril/analysis , Potentiometry , TabletsABSTRACT
A method for the coulometric determination of primaquine is presented. The coulometric titration is carried out in the anode compartment, in the supporting electrolyte consisting of 0.5 M sulfuric acid and 0.2 M sodium chloride solution, in the presence of methyl orange as indicator. The electrogenerated chlorine reacts with primaquine in a 2:1 molar stoichiometric ratio. Accurate and reproducible results have been obtained in the assay of small amounts of primaquine. One coulomb corresponds to 1.1797 mg of primaquine diphosphate.
Subject(s)
Antimalarials/analysis , Primaquine/analysis , Chlorine/chemistry , Electrochemistry , Indicators and Reagents , Primaquine/analogs & derivatives , Reproducibility of ResultsSubject(s)
Methimazole/analysis , Electrochemistry , Electrolytes/analysis , Indicators and ReagentsABSTRACT
A method of conductometric titration for determination of methenamine is presented. An aqueous solution of silicotungstic acid is used as titrant. The acid and methenamine form an insoluble compound in which the molar ratio of the acid to methenamine is 1:4. Conductometric curves were obtained, the shapes of which are suitable for accurate and reproducible determination of the end point of titration. The results show reasonable accuracy. Good reproducibility was achieved even when small quantities of methenamine had to be determined.
