Electrical characterization of functionalized platinum electrodes and ISFET sensors for metal ion detection

This paper reports the application of functionalized platinum (Pt) electrodes and ChemFETs sensors for metal ion detection. The sensitive part of the sensors consists in a film of ethyl 2-thienylglyoxalate (ETGO) deposited by a spin-coating process. Electrochemical impedance spectroscopy was used to investigate the electrical properties of functionalized Pt electrodes. The optimized working conditions of the sensors have been studied with regard to the sensitivity performances, in particular, the polarization was adjusted to − 0.85 V/ESC in order to neglect the Warburg effects at low frequencies. The functionalized Pt electrodes have shown a good sensitivity towards Cu(II) ions, whereas low response towards Ca(II) ions was observed. The ETGO/ISFET devices have shown good sensitivity (14 mV/decade) and linear responses over at least two decades of Cu(II) activity compared to (0.5 mV/decade) for Ca(II) ions.