Low-Cost and Disposable Electrochemical Detection Based on PCB and SPCE for Multi-Ion Detection: A Comparative Study for Multiplexed Sensing

Abstract

This study presents the development of a multi-ion selective electrode system based on a printed circuit board (PCB) substrate integrated with a gold conductive layer, aiming to achieve reliable, high-throughput electrochemical sensing. The electrochemical performance of the PCB-based electrodes was systematically compared to that of conventional screen-printed carbon electrodes (SPCEs) under identical ion-selective membrane conditions. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) revealed that the PCB electrodes exhibited significantly lower charge transfer resistance (Rct), solution resistance (Rs), and peak-to-peak potential separation (ΔEp), indicating enhanced redox reversibility and interfacial conductivity. In open-circuit potential (OCP) measurements, the PCB-based electrodes showed superior potential stability, with markedly reduced variation in initial potentials (0.5~17.6 mV) compared to SPCEs (34.2~114.3 mV) across repeated trials and electrode units. To validate the sensor’s multiplexing capability, an 8-channel electrode array was fabricated on a single PCB substrate, with each electrode modified using a distinct ion-selective membrane specific to one of eight target ions. The resulting system enabled reliable detection of all eight ions, confirming the platform's effectiveness as a cost-efficient, high-throughput solution for multi-ion electrochemical sensing. These findings highlight the advantages of PCB-based sensor systems in terms of electrochemical performance, scalability, and integration potential for environmental, biological, and agricultural applications.