| 要約: | Performance drift in electrochemical sensors remains a challenge in long-term and/or corrosive applications. We present a generalisable, in situ diagnostic framework based on electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV), using screen-printed electrodes (SPE) and benzenediols (catechol, resorcinol and hydroquinone) in acidic media as a model system. Two sensor types, unmodified and Pt/C-modified SPEs, were tested across repeated CV cycles, with polarisation resistance (RP) and effective capacitance (Ceff) extracted from equivalent circuit models.Unmodified SPEs showed progressive activation, while modified SPEs exhibited early improvement followed by degradation. To synthesise trends across RP, Ceff, and net charge transfer (Qₙ) obtained from CV data, principal component analysis (PCA) was applied. PCA revealed smooth, directional evolution for unmodified SPEs and disordered, non-monotonic drift in modified SPEs, reinforcing the EIS results.This approach enables online, non-destructive tracking of electrochemical sensor health and offers a transferable framework for performance assurance, quality control, and lifecycle monitoring. It repositions EIS from static characterisation to an embedded, multivariate diagnostic tool.
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