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We fabricated a highly sensitive electrochemical sensor for the determination of bisphenol A (BPA) in aqueous solution by using reduced graphene oxide (RGO), carbon nanotubes (CNT), and gold nanoparticles (AuNPs)‐modified screen‐printed electrode (SPE). GO/CNT nanocomposite was directly reduced to RGO/CNT on SPE at room temperature. AuNPs were then electrochemically deposited in situ on RGO/CNT‐modified SPE. Under optimized conditions, differential pulse voltammetry (DPV) produced linear current responses for BPA concentrations of 1.45 to 20 and 20 to 1,490 nM, with a calculated detection limit of an ultralow 800 pM. The sensor response was unaffected by the presence of interferents such as phenol, p‐nitrophenol, pyrocatechol, 2,4‐dinitrophenol, and hydroquinone.

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In the electrospinning process, unstructured nanofiber mats are produced by oriented fluid jets with an external electrostatic field. Electrospun fibers have wide applications for the fabrication of composite materials, tissue scaffold, and membranes. However, electrospun fiber production systems have many problems, e.g., the bending instability due to the complicated oscillations of polymer jet. In this research, parallel plate and hollow cylindrical conducting electrodes are implemented through the jet trajectory in order to investigate the possibility of controlled deposition of polymer fibers. Parallel electrodes with proper driving sources can generate the steering field for the nanofiber formation at the collector plate based on analog addressing electronics. It was shown that the modulated electric field applied through the parallel plate electrodes notably increased the deposition of the electrospun polymer fibers in a controlled fashion at the collector, which is coherent to the computer simulations. Furthermore, the finite-length hollow cylinder dampened the bending instabilities of the polymer jet which decreases the characteristic spot size of the deposited electrospun fiber to a smaller diameter.