PAPAVERINE-SELECTIVE PLASTIC MEMBRANE-ELECTRODE BASED ON PAPAVERINIUM TETRAPHENYLBORATE

A plasticized PVC membrane containing the lipophilic salt papaverinium-tetraphenylborate was used to construct an ion-selective electrode for papaverine hydrochloride (Pv+Cl-). The electrode shows near Nernstian response over the concentration range 1.6 x 10(-5) - 1.30 x 10(-2) M PvCl in solutions of pH 1.0-6.2 at 25-degrees-C. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode. The electrode showed very good selectivity for Pv with respect to a large number of inorganic and organic cations. The potentiometric titration and standard addition methods were used to determine Pv in pure solutions and in pharmaceutical preparations.