Solution ion luminescence induced by the triboelectric-discharge effect for rapid and intuitive detection of sweat ions

Sweat ion detection is a non-invasive health monitoring technique widely used in areas, such as sports monitoring, disease diagnosis, and drug treatment assessment. State-of-the-art technologies, such as ion-selective electrode analysis, chromatography, and spectroscopy, usually rely on specific biomaterials, large equipment, or highly skilled operators, limiting their lifespan and application scenarios. To address these challenges, this work proposed a triboelectric-discharge effect-enabled, visualized sweat ion detection solution with the merits of a simple design, user-friendliness, real-time monitoring, reusability, self-powering, with no need for additional materials. The visible light of ion luminescence with various ionic information can be excited by inducing triboelectric discharge between a metal tip and the sample solution. The species and concentrations of ions were identified by the colors and eigen-peaks of the luminescence. Additionally, the effectiveness of this method was further verified by testing artificial sweat doped with lithium ions and varying concentrations of potassium ions, demonstrating its potential for sweat ion analysis and health assessment in a rapid and intuitive way.