Highly selective sensing of dopamine using carbon nanotube ink doped with anionic surfactant modified disposable paper electrode

An unconventional, flexible, disposable paper-based selective sensing platform for dopamine in the presence of ascorbic acid, suitable for wearable electronics, has been described for the first time in this work. The carbon nanotube ink-modified paper (CNIMP) in the presence of an anionic surfactant was able to discriminate effectively between dopamine and ascorbic acid thereby alleviating the difficulties associated with the sensing of dopamine in the presence of high concentration of ascorbic acid which undergoes oxidation at similar potential. The CNIMP electrode provided a large surface area in addition to its flexibility and disposability which was 25 times higher compared to a glassy carbon electrode of the same geometric area. The conductivity of the CNIMP electrodes as measured by four probe conductivity measurements was reasonably high of the order of 1.7 × 10^?2 S cm^?1 facilitating its usefulness for the development of flexible sensors. The microscopic features of the electrodes showed the dense coverage and even distribution of carbon nanotubes on the surface with the surfactant molecules uniformly encapsulated on the surface.