Electrochemical Analysis of Methanol with Nafion-Coated Copper Oxide Nanoparticles

This work introduces a Nafion-coated copper(I) oxide nanoparticle electrode (Nafion/Cu₂O/GC) designed for the electrochemical detection of methanol (CH₃OH). The responses of the composite material toward CH₃OH were enhanced by the selective permeation of CH₃OH through the hydrophilic channels of the Nafion membrane in combination with the electroactivity of Cu₂O nanoparticles. The sensor displayed a linear detection range of 0.33-100 mM CH₃OH with a sensitivity of 0.17 μA·mM^-1 and a detection limit (3 s/m) of 0.10 mM. It exhibited excellent reproducibility with a relative standard deviation of <5%. The sensor's practical applicability was demonstrated through recovery studies on hand sanitizer samples, achieving ca. 100% recovery. The sensor was further used to elucidate CH₃OH adsorption on activated carbon, revealing that the process conforms to the Langmuir isotherm model.