Monitoring impulsional pH variations in microvolumes: A new approach for the electrochemical detection

This paper presents a new electrochemical sensor, named ElecFET (electrochemical field effect transistor), combining amperometric and potentiometric detection principles thanks to the functional integration of an electrochemical microelectrode with a pH-ChemFET microdevice. Thus, by triggering water-based electrolysis phenomena thanks to the integrated microelectrode, impulsional pH variations in microvolumes were evidenced by pH-ChemFET-metry and studied according to the main polarization parameters, i.e. voltage and duration. The ElecFET detection principles were finally extended to the detection of hydrogen peroxide H₂O₂ in solution, evidencing a 1.25 mV/mM sensitivity in the [10-100 mM] concentration range.