Preparation of PVC Membrane Electrodes

In the preparation of PVC-stabilized electrodes with neutral ligands a lower concentration of the active compound is usually applied. In these cases a Nernstian response is only obtained if an additional plasticizer is added. For example, 0.2 g PVC, 

5 mg special ligand (see Fig. 12) and 0.2 g plasticizer are dissolved in 6 ml tetrahydrofuran, and the solution is allowed to evaporate from a 48 mm inner diameter petri dish to yield a selective membrane about 1.5 mm thick. Dibutylphthalate has proven to be a better plasticizer than tributylphosphate or diphenyl ether [139]. By using less polar plasticizers (such as dipentylphthalate, e 5) shorter response times can be attained [140]. 

---