Polysiloxane based CHEMFETs for selective detection of Ca2+ ions

Different siloxane copolymers have been used as membrane materials for Ca2+ selective chemically modified field effect transistors (CHEMFETs). CHEMFETs with 3-benzoylaminopropyl-functionalized polysiloxane membranes and 1 wt% borate anions are intrinsically selective for Ca2+ ions. This selectivity can be further enhanced by the incorporation of a Ca2+ selective 1,3 alternate calix[4]arene which is functionalized with four amido groups. The highest Ca2+ selectivties were obtained with CHEMFETs containing this calix[4]arene ionophore in 3-cyanopropyl-functionalized polysiloxane membranes.