Impedimetric blood pH sensor based on MoS2–Nafion coated microelectrode

Abstract

Ion selective electrodes are a good alternative to glass-based pH sensors to replace traditional bulky pH sensors with compact and robust point of care analyzers. This is especially important for healthcare applications, as the pH-sensing element of hand-held blood gas analyzers to aid blood gas analysis in remote or mobile medical set ups. In this work, we have presented an impedimetric pH sensor consisting of parallel coplanar electrodes of aluminum coated with molybdenum disulfide (MoS₂) nanoparticles and Nafion as a permselective layer. This sensor showed a sensitivity of 6193 Ω pH⁻¹ and a response time of 4 s on testing with Sorensen’s phosphate buffers at different pH values, used as a physiological buffer. A preliminary study of the sensor with capillary blood shows that its estimated pH lies close to that of the venous blood pH, thus showcasing good characteristics to be a potential candidate for the pH-sensing element of a point of care analyzer.