Construction and analytical applications of plastic membrane electrodes for oxytetracycline hydrochloride

Oxytetracycline hydrochloride-selective electrodes of both the coated wire and the conventional polymer membrane types based on oxytetracyclinium phos photungstate and phosphomolybdate have been prepared. A Nernstian response is shown by these electrodes within 1.0 x 10(-6) - 1.0 x 10(-2) M concentra tion ranges depending on the type of electrode. The response is unaffected by the change of pH over the range 4-11. The standard electrode potentials, E degrees, were determined at different temperatures and used to calculate the isothermal temperature coefficients of the electrodes, The electrodes show good selectivity to oxytetracycline hydrochloride with respect to many inorganic cations, sugars and amino-acids. Oxytetracycline hydrochloride i s determined successfully in pure solutions and in pharmaceutical preparati ons using calibration by standard addition and potentiometric titration. A regeneration process for the exhausted electrodes has been developed.