Comparison of thiacalix[4]arene thin films behaviour on different transducers for copper ion detection

Thin thiacalix[4]arene films were deposited using a thermal evaporation technique in vacuum in order to functionalize different transducers: EIS, ISFETs and gold electrodes for copper ion detection. Electrochemical measurements allowed to characterise the membrane sensibility towards Cu(II) ions. The sensors based on thiacalix[4]arene/semiconductor transducers (ISFET, EIS) have shown a Nernstian response towards Cu(II) with a detection limit of about 10−5 M. The functionalized gold electrode was used as copper sensor, several conditions were optimized in order to enhance the sensitivities at low concentrations. In particular, the polarisation of the electrode was adjusted in order to neglect the Warburg effects at low frequencies. The thiacalix[4]arene/gold electrodes have shown a good sensitivity and a low detection limit of about 10−7 M which has to be compared to the behaviour obtained with ISFET and EIS type sensors.