Wireless wearable potentiometric sensor for simultaneous determination of pH, sodium and potassium in human sweat

This paper reports on the development of a flexible-wearable potentiometric sensor for real-time monitoring of sodium ion (Na⁺), potassium ion (K⁺), and pH in human sweat. Na_0.44MnO₂, polyaniline, and K₂Co[Fe(CN)₆] were used as sensing materials for Na⁺, H⁺ and K⁺ monitoring, respectively. The simultaneous potentiometric Na⁺, K⁺, and pH sensing were carried out by the developed sensor, which enables signal collection and transmission in real-time to the smartphone via a Wi-Fi access point. Then, the potentiometric responses were evaluated by a designed android application. Na⁺, K⁺, and pH sensors illustrated high sensitivity (59.7 ± 0.8 mV/decade for Na⁺, 57.8 ± 0.9 mV/decade for K⁺, and 54.7 ± 0.6 mV/pH for pH), excellent stability, and good batch-to-batch reproducibility. The results of on-body experiments demonstrated that the proposed platform is capable of real-time monitoring of the investigated ions.