Tetracycline sensitive membrane electrodes based on poly (vinyl chloride) matrices and their use in drug analysts

Tetracycline hydrochloride-selective electrodes of both the coated wire and the conventional polymer membrane types have been prepared. They are based on incorporating the tetracycline-phosphotungstate ion-associate in plasti cized poly(vinyl chloride) film. A Nernstian response is shown by these ele ctrodes within certain concentration ranges depending oft the type of elect rode. The effect of pH of the test solution and time of soaking on the elec trodes' performance are studied. The electrodes are highly selective for te tracycline with respect to several inorganic cations, sugars and some amino -acids of significant importance in biological fluids and pharmaceutical pr eparations. The standard cell potentials, E degrees, were determined at dif ferent temperatures and used to calculate the isothermal temperature coeffi cient of the cell. Tetracycline is determined successfully in pure solution s and in pharmaceutical preparation using the standard additions method and potentiometric titration.