Comparative Study of Planar Ag/AgCl Quasi-Reference Electrodes Developed on PCB

This paper presents a comparative study of different fabrication methods for planar Ag/AgCl quasi-reference electrodes (RE) on a printed circuit board (PCB) aimed at integration into portable electrochemical biosensors. Three fabrication techniques based on electroplating and screen printing are studied, along with two chlorination methods to convert the electroplated silver layers into silver chloride layers. The comprehensive characterisation of the three REs demonstrates the stability of the electrodes compared to those of commercially available planar reference electrodes. A drift rate as low as 2.2 mV/day is observed over 7 days for electrodes developed through Ag electroplating and chlorination with NaOCl, making these REs suitable for continuous biosensing applications.