Efficient strategy for quality control of screen-printed carbon ink disposable sensor electrodes based on simultaneous evaluation of resistance, capacitance and Faradaic current by Fourier transform AC voltammetry

Abstract

Two types of mass-produced, screen-printed carbon ink-based macrodisc electrodes suitable for routine sensing applications have been fabricated. Microscopic examination of these carbon ink electrode surfaces reveals that their surfaces are both rough and highly heterogeneous, consisting of random arrays of carbon particles of different sizes, as well as binder. Consequently, they may suffer from a lack of reproducibility in their performance because of variable resistance, capacitance or electroactive area. Use of a Fourier transform AC voltammetric protocol involving application of periodic waveform obtained from summation of five sine waves of variable frequency enabled resistance and capacitance, as well as DC and AC Faradaic currents associated with the model processes \({\text{FcMeOH}} \rightleftarrows {\text{FcMeOH}}^{\text{ + }} + {\text{e}}^ - \) or \(\left[ {Ru\left( {NH_3 } \right)_6 } \right]^{3 + } + e^ - \rightleftarrows \left[ {Ru\left( {NH_3 } \right)_6 } \right]^{2 + } \) (where FcMeOH is ferrocene methanol) to be assessed from a single experiment. Such data, which may be obtained rapidly via this approach, are highly suitable for quality control assessment.