Quantum capacitance sensing

A sensing method comprising:

• (A) obtaining, by electrochemical impedance spectroscopy conducted across a range of applied potentials, a plurality of measurements of the complex impedance, Z*, of a system that has a working electrode that comprises an electrode substrate functionalised with sensing elements whose electrochemical response to the applied potentials is sensitive to a change in the local environment of the electrode, the sensing elements having a dimension of from 0.5 to 10 nm;
• (B) converting said plurality of measurements of Z* into a plurality of measurements of the real component of the complex capacitance, C′, at a selected frequency ω and/or the imaginary component of the complex capacitance, C″, at a selected frequency ω;
• (C) integrating the measurements of (a) C′, (b) C″, or (c) any combination of C′ and C″, at the selected frequency ω as a function of applied voltage to obtain an integrated measurement value;
• and
• (D) evaluating the local environment of the electrode from said integrated measurement value.

An apparatus for use in a sensing method, which apparatus comprises:

• an electrochemical spectrometer that comprises a working electrode, a counter electrode and a potentiostat, wherein said working electrode comprises an electrode substrate functionalised with sensing elements whose electrochemical response to applied potentials is sensitive to a change in the local environment of the electrode, the sensing elements having a dimension of from 0.5 to 10 nm;
• a receiver configured to receive, from said electrochemical spectrometer, input data comprising:
• a plurality of measurements of complex impedance, Z*, across a range of applied potentials;
• and
• a processor configured to (i) convert said plurality of measurements of Z* into a plurality of measurements of the real component of the complex capacitance, C′, at a selected frequency ω and/or the imaginary component of the complex capacitance, C∴, at a selected frequency ω, and (ii) integrate said measurements of (a) C′, (b) C″, or (c) any combination of C′ and C″, at the selected frequency to as a function of applied voltage to obtain an integrated measurement value.

A storage medium storing computer readable code for implementation by a computer or network of computers, the code, when implemented, causing the computer or network of computers to implement the steps of;

• obtaining, from an electrochemical spectrometer, input data comprising a plurality of measurements of complex impedance, Z*, across a range of applied potentials;
• converting said plurality of measurements of Z* into a plurality of measurements of the real component of the complex capacitance, C′, at a selected frequency ω and/or the imaginary component of the complex capacitance, C″, at a selected frequency ω;
• and
• integrating said measurements of (a) C′, (b) C″, or (c) any combination of C′ and C″, at the selected frequency ω as a function of applied voltage to obtain an integrated measurement value.