Supported sol-gel-derived membranes for neutral carrier-type ion-selective electrodes

For neutral carrier-type ion-selective electrodes, several sol-gel-derived membranes were designed which encapsulate valinomycin and bis(crown ether) derivatives as the neutral carriers. Relatively large size ion-sensing membranes based on sol-gel-derived glass were successfully fabricated by using membrane filters and sintered glass filters as the membrane supports. Potassium and sodium ion-selective electrodes, at the tip of which sol-gel-derived membranes containing a neutral carrier and a poly(tetrafluoroethylene) membrane filter were incorporated, exhibit high electrode performance in their sensitivity, selectivity, and response time. The supported sol-gel-derived membranes were also modified chemically by alkoxysilylated bis(crown ether) derivatives and were tested for their usefulness as sensing membranes of ion-selective electrodes.