STUDY OF ION-SELECTIVE EVAPORATED CALIXARENE FILM USED AS A SENSITIVELAYER ON ISFET SENSORS

Thin calix[4]arene and calix[6]arene films were deposited using the te chnique of thermal evaporation under vacuum to fabricate chemical ion- selective field effect transistor (ISFET) microsensors. A high-perform ance liquid-phase chromatography (HPLC) method was used to verify the non-degradation of the calixarene layers, after the evaporation proces s. The sensing properties of these ionophores towards alkaline and hea vy metal ions were tested. Both devices have shown Nernstian response and a wide working pH range. The former responded well to sodium ions and the latter to nickel ions, thus partial selectivity for these ions is shown. The improved lifetime membranes and sensitivity observed fo r these films indicates that these structures are worthy of further de velopments. (C) 1998 Elsevier Science S.A. All rights reserved.