Flexible electrochemical sensor based on a ZnO-doped SnO2 heterojunction for simultaneous electrochemical determination of p-aminophenol and acetaminophen

In this work, a novel flexible electrochemical sensor was successfully developed for the simultaneous determination of p-aminophenol and acetaminophen. The sensor is composed of a methanesulfonic acid-treated poly (3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid) film on a poly(ethylene terephthalate) substrate, which has been modified using a zinc oxide-doped tin oxide heterojunction applied through drop-coating (C-ZnO/SnO2-PEDOT/PET). The oxygen vacancies resulting from zinc oxide-doped tin oxide heterojunctions within highly conductive metal oxide nanomaterials enhance mass transfer and synergize seamlessly with methanesulfonic acid-treated electrically conductive dielectric PEDOT/PET films, leading to a substantial improvement in electrochemical activity. Under the optimal conditions, a wider linear range and lower detection limits were shown for p-aminophenol (2-511 mu M, LOD=0.437 mu M) and acetaminophen (2-591 mu M, LOD=0.562 mu M). In addition, the sensors demonstrated high accuracy in detecting p-aminophenol and acetaminophen in real samples, with recoveries of 99.36 %-99.60 % and 97.56 %-99.80 %, respectively. Furthermore, the flexible sensors maintained a superior electrochemical response when detecting p-aminophenol and acetaminophen at different bending angles, with relative standard deviations of 0.62 % and 1.68 %, respectively. These findings suggest potential applications for the development of wearable sensors in the future.