ISFET USING PVC-BASED ION SELECTIVE MEMBRANES.

Ion-selective membranes based on a polymer matrix have been applied to various ion-selective electrodes. Some of the advantages of these electrodes are: higher selectivity and superior applicability to physiological samples. In this study, the insulating membrane at the gate of ISFET was covered with a PVC-based ion-selective membrane and the characteristics of the ISFET were assessed. The prototype ISFET's for Na plus , K plus , and C L-SCRIPT minus were prepared by a dip coating method. A synthetic ligand, valinomycin, and a quaternary ammonium salt were used as ion-selective substances for Na plus , K plus and C L-SCRIPT minus , respectively. Though Na plus - and C L-SCRIPT minus - FET's had inferior slopes (46m V/p Na plus , and 40m V/p C L-SCRIPT minus ), K plus -FET showed a good slope (55m V/p K plus ) and good selectivity over Na plus .