Plastic membrane selective electrodes for chlortetracyclinium ion based onchlortetracyclinium-phosphotungstate and phosphomolybdate ion-pair associates

Chlortetracycline-selective electrodes of both the coated wire and the conv entional polymer membrane types based on chlortetracyclinium-phosphotungsta te and phosphomolybdate have been prepared, A Nernstian response is shown b y these electrodes within 1.0 X 10(-6)-1.0 X 10(-2) mol dm(-3) concentratio n ranges depending on the type of electrode. The change of pH within the ra nge (5.5-11.5) does not affect the electrode performance. The standard elec trode potentials, E, were determined at different temperatures and used to calculate the isothermal temperature coefficients of the electrodes. The el ectrodes show good selectivity to chlortetracycline hydrochloride with resp ect to many inorganic cations, sugars and amino acids. Chlortetracycline hy drochloride is determined successfully in pure solutions and in pharmaceuti cal preparations using the standard additions method and potentiometric tit ration. Regeneration process for the exhausted electrodes is successfully a pplied.