The solid contact ion selective electrodes are different from the liquid contact ion selective electrodes by replacing the inner filling solution with solid-state ion-to-electron transducers. In this thesis, two different types of ion-to-electron transducers are introduced. The first is the multi-walled carbon nanotubes modified with alkyl group for fabrication of solid contact electrodes for on-line and in-situ potentiometric detection of environmental anions (e.g., chloride, carbonate, nitrate). The second utilizes the electropolymerized poly (3-octylthiophene) for voltammetric study of ion transfer process between membrane and solution interface. By proper experimental design, the voltammetry experiment could be a useful technique for probing the ion-ionophore interactions inside the membrane. In addition to the research of solid contact ion selective electrodes, robust boundary element calculations in the computer simulations of ion exchange process for ion selective membrane are also described.