Zekra Mousavi

Analytical quality solid-state composite reference electrode manufactured by injection moulding

An injection moulding method was used for fabricating solid-state reference electrodes (Ag/AgCl type) based on a polymer/inorganic salt composite. In this method, a silver/silver chloride wire was placed inside a mould into which the mixture of polymer and inorganic salt was injected. The obtained solid-state composite reference electrodes were extensively tested to study the influence of different parameters such as solution composition, the concentrations and mobility of ions and pH on the potential stability of the electrodes. These experiments revealed that the composite reference electrodes are insensitive to the matrix effect, have excellent potential readings stability and considerably reduced leakage of inorganic salt. The composite reference electrodes were compared favourably to high-quality commercial reference electrodes. It was concluded that the composite reference electrodes obtained by injection moulding are of analytical quality allowing for continuous, prolonged and intensive usage.

All-solid-state Potassium Ion-selective Electrode with Conducting Polymer Doped with Carbon Nanotubes and C60 as the Ion-to-Electron Transducing Layers

In solid-contact ion-selective electrodes the ionto-electron transduction takes place in a solid and compact layer between the ion conducting ion-selective membrane and the electron conducting metallic or carbon substrate. In conventional ion-selective electrodes, ISE, the ion-to-electron transduction takes place in the internal reference electrode. Conducting polymers doped with different anions are frequently used as the transduction layer. Potentiometric sensors including polymer based electrodes have recently been reviewed. Carbon based materials have also been used as the ion-to-electron transducing layer.

Sensitivity and Selectivity of Ion-Selective Electrodes Interpreted Using the Nernst-Planck-Poisson Model

The Nernst-Planck-Poisson model is used for modeling the sensitivity and selectivity of ion-selective electrodes (ISEs) with plastic membranes. Two pivotal parameters characterizing ISE response are in focus: sensitivity and selectivity. An interpretation of sensitivity, which considers the concurrent influence of anions and cations on the ISE slope, is presented. The interpretation of selectivity shows the validity and limits of approaches hitherto taken to measure the true (unbiased) selectivity coefficient. The validity of more idealized interpretations by the diffusion-layer model is conceived.