Construction and Application of a PVC Membrane Enoxacin Ion－selective Electrode Based on a Needle－shaped Inner Reference Electrode

IntroductionPVC membrane- coated- wire electrodes areused in the analytical field widely. They are pre-pared usually with platinum wire,silver wire orgraphite rod coated with a PVC thin membranecontaining various active components and plasticiz-ers1— 3 ] .The electrodes have no inner KCl solutionand they are notinfluenced by the sample pressure.Furthermore,they are free from directional selec-tivity when they are installed,and they can be mi-crominiaturized easily. The shortcomings of th…

Construction and Application of a PVC Membrane Enoxacin Ion-selective Electrode Based on a Needle-shaped Inner Reference Electrode

A PVC membrane enoxacin ion-selective electrode based on a needle-shaped inner reference electrode was prepared. A Ag/AgCl wire was used as the substrate of this electrode. It was previously coated with a thin sheet of urea-formaldehyde resin containing Cl- ions to form a needle-shaped inner reference electrode, then the inner reference electrode was coated with a thin sheet of a PVC membrane containing an enoxacin tetraphenylborate ion-pair complex. The influences of various ion-pair complexes, concentrations of the active components in the membrane and the plasticizers on the performance of the electrode were studied by orthogonal design. The linear response range of the electrode was 7.9×10-5-1.0×10-2 mol/L. The detection limit was 2.0×10-5 mol/L. The slope was 30.4 mV/decade(25 ℃). The electrode can be used for the potentiometric determination of enoxacin tablets directly. The average recovery was 100.4%, and the RSD was 0.9%. The results agreed with those determined by the method in Chinese Pharmacopoeia.