A graphene-based electrochemical detection platform for monitoring the change of potassium content in sweat during exhaustive exercise

In this investigation, we developed an ion-selective electrode-based potassium ion sensor for the detection of potassium ions in sweat, and evaluated its selectivity and stability. The sensor was fabricated through in-situ polymerization of 3,4-ethylenedioxythiophene (EDOT) monomer on a graphene-modified glassy carbon electrode using a constant current method. This was followed by the application of a potassium ion-selective membrane to form a poly(3,4-ethylenedioxythiophene) (PEDOT) modified potassium ion sensing electrode. The physical morphology and electrochemical properties of the sensor were characterized using scanning electron microscopy (SEM) and an electrochemical workstation. The results indicated that the conductivity of the PEDOT modified electrode was significantly enhanced, and the potassium ion sensor exhibited a near-Nernstian response over the range of 1–40 mM potassium ion concentration. The sensor demonstrated good repeatability, reproducibility, long-term stability, and high selectivity against interference from sodium ions, glucose, dopamine, and urea.