Sensitivity-enhanced potentiometric measurement by incorporating graphitic carbon nitride into the ion-to-electron transducer of potassium ion-selective electrodes.

Abstract

In recent years, wearable sweat sensors have garnered significant attention for real-time monitoring of human physiological information because of their ability to continuously and non-invasively detect multiple sweat biomarkers. Among these, potentiometric sensors stand out for their low power consumption, low cost, compact design, and real-time monitoring capabilities, making them an ideal alternative for sweat analysis. However, enhancing the sensitivity of ion-selective electrodes (ISEs), a critical parameter of potentiometric sensors, remains a challenging research focus. In this work, the sensitivity of K⁺ ISEs was significantly enhanced by doping two-dimensional nanoparticles graphitic carbon nitride (g-C₃N₄) into the ion-to-electron transducer of the electrode via electrodeposition. The calibration curve slope of the K⁺ potentiometric sensors with doped g-C₃N₄ reached 59.6 mV/dec, representing a 33% increase in sensitivity compared to the control sensor without g-C₃N₄. Furthermore, the developed sensors demonstrated excellent repeatability, and anti-interference capabilities. Finally, the feasibility of the prepared sensors was further validated in artificial sweat. The large specific surface area of g-C₃N₄ combined with the excellent conductivity of PEDOT: PSS, significantly improved the sensitivity of ISEs in this study. This innovative approach paves a new avenue for the application of two-dimensional materials in potentiometric sensors, potentially advancing the field of real-time sweat analysis.