Click-immobilized K+-selective ionophore for potentiometric and optical sensors

Clickable crown ether type of K+-selective ionophore was synthesized for the first time. The ionophore can be easily immobilized in azide-modified poly (vinyl chloride) (N3PVC) matrix by azide-alkyne Huisgen cycloaddition (“click chemistry”) for the fabrication of potentiometric and optical sensors. Formation of the triazole linkers in the polymer matrix decreases the solubility of functionalized PVC significantly. Azidation of PVC for 12 h followed by Cu(I) catalyzed cycloaddition can produce ionophore grafted PVC with good solubility and film forming property. The solid-contact electrode prepared with plasticized functional polymer exhibited Nernstian response to potassium ion from 10−6 to 10−1 M, good selectivity and improved lifetime. Such ionophore grafted polymer has also been used to prepare optical sensors with ETH 5294 as chromoionophore. The measuring range and selectivity of the optode are comparable to the ones of ion-selective electrode.