The field of biochemical sensing is evolving from the use of bulky apparatuses to the development of miniaturized systems allowing personal sensing and point of care analysis. We report a wearable platform capable of measuring the concentration of multiple electrolytes in sweat (Na+, K+, Cl−). The platform accesses sweat emerging through the skin, drawing it across solid-state ion-selective electrodes by capillary action. The electrolyte composition is monitored in real time by potentiometry. The sensor data is digitised and transmitted via Bluetooth to a mobile phone or laptop. The platform has been employed in on-body trials during controlled exercise.
