SUITABLE ION-SELECTIVE SENSORS FOR LEAD AND CADMIUM ANALYSIS

Two different chemical sensor assemblies for lead(II) and cadmium(II) ions have been fabricated. The first is based on a traditional ion-selective electrode and the second on a graphite solid-state device. Both chemical sensors have been characterized and tested in standard solutions and also in river water samples. The use of a PVC-PVA-PVAc copolymer as base polymer in the membrane allows us to get a better adhesion on the graphite active surface of the device. The selectivity in the modified membrane is given using derivatives of dioxa diamide or ditioamide. The results obtained by the solid-state chemical sensors are compared with those obtained by ion-selective electrodes. Potentiometric measurements, response time, lifetime, linearity range and selectivity factors have also been reported and discussed.