A Solid-Contact Reference Electrode Based on Silver/Silver Organic Insoluble Salt for Potentiometric Ion Sensing

Shiyu Gan; Chunxian Liao; Rongfeng Liang; Sanyang Du; Lijie Zhong; Yitian Tang; Tingting Han; Yu Bao; Zhonghui Sun; Yingming Ma; Li Niu

doi:10.1021/acsmeasuresciau.2c00036

A Solid-Contact Reference Electrode Based on Silver/Silver Organic Insoluble Salt for Potentiometric Ion Sensing

ACS Meas Sci Au. 2022 Aug 16;2(6):568-575. doi: 10.1021/acsmeasuresciau.2c00036. eCollection 2022 Dec 21.

Authors

Affiliation

¹ Guangzhou Key Laboratory of Sensing Materials & Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.

Abstract

Solid-contact ion-selective electrodes are a type of ion measurement devices that have been focused in wearable biotechnology based on the features of miniaturization and integration. However, the solid-contact reference electrodes (SC-REs) remain relatively less focused compared with numerous working (or indicator) electrodes. Most SC-REs in wearable sensors rely on Ag/AgCl reference electrodes with solid electrolytes, for example, the hydrophilic electrolyte salts in polymer matrix, but face the risk of electrolyte leakage. Herein, we report a type of SC-REs based on the silver/silver tetraphenylborate (Ag/AgTPB) organic insoluble electrode. The SC-RE consists of a Ag substrate, a solid contact (AgTPB), and a plasticized poly(vinyl chloride) (PVC) membrane containing the hydrophobic organic salt of tetrabutylammonium tetraphenylborate (TBATPB). The potentiometric measurements demonstrated that the SC-RE of Ag/AgTPB/PVC-TBATPB showed a reproducible standard potential in various electrolytes and disclosed high long-term stability. This SC-RE was further fabricated on a flexible substrate and integrated into all-solid-state wearable potentiometric ion sensor for sweat Cl^- monitoring.