Optimization and characterization of nanostructured paper-based electrodes

Paper-based working electrodes were modified by the addition of nanomaterials (carbon nanofibers, gold nanoparticles, graphene and hybrids of them), with the aim to increase the conductivity and to obtain an electroactive platform with improved analytical behaviour. The effect of the nanostructures was evaluated by using cyclic voltammetry and dopamine as electrochemical probe. The modifications with in-situ generated nanomaterials such as gold nanoparticles (AuNPs) or others requiring treatment like graphene oxide (GO), were optimized by factorial design. The characterization of the cellulose based electrodes by scanning electron microscopy (SEM) showed the distribution of carbon nanofibers and the presence of AuNPs around the cellulose fibers. The partial modification made by the carbon ink was also monitored by attenuated total reflection (ATR) spectrometry. Electrodes modified with rGO and AuNPs exhibited higher intensity peaks with more reversibility and reproducibility than unmodified paper. The highest intensities and lowest limits of detection were achieved with paper electrodes modified with hybrid nanostructures composed by both CNFs and AuNPs.