Ion Selective PVC Membrane Electrode for the Determination of Methacycline Hydrochloride in Pharmaceutical Formulation

Abstract

A plastic membrane electrode for the determination of methacycline hydrochloride was fabricated based on the use of methacycline-tetraphenylborate as the electroactive substance, and dioctylphtalate as the plasticizing agent. It was found that the potential responses of the electrode were influenced by pH of the tested solution when pH>3. Under the condition of pH 2.6, the linear response range, slope (25ºC) and detection limit obtained were 3.0×10^-2~6.0×10^-6M, 52.9mv per decade and 3.4×10^-6M ,respectively. The response time of the electrodes was <15 seconds. The values of recovery obtained were 99.2~101.2%. The electrode was successfully applied to determination of methacycline hydrochloride in tablet by direct potentiometric method. The result obtained with the electrode was in good agreement with the value obtained by using the official method (highperformance liquid chromatography).