Effect of Nature of Polymeric Matrix on the Impedimetric Detection of Cobalt with a Calix[6]arene Based Membrane/Gold Electrode

This work describes the attempts to develop a new type of modified electrode with high sensitivity towards cobalt ions, Co2+. The method is based upon the use of calix-[6]-arene, which is a macrocyclic molecule composed of six phenol units. Polyvinylchloride (PVC), and Polymethylhydrosiloxane (PMHS) were the polymers used and deposited as thin membranes incorporating calix-[6]-arene, on gold electrode. The electrical properties of the polymeric membrane have been characterized by electrochemical impedance spectroscopy (EIS). Linear ranges are respectively 10(-9) M to 10(-6) M for PVC based membrane and 10(-9) M to 10(-7) M for PMHS based membrane. The detection limit is about 10(-9.2) M for PVC based sensor and 10(-9) M for the PMHS based sensor. PMHS based membranes led to more sensitive cobalt sensor compared to PVC based membranes.