In this study, functionalized bimetallic Au-Pd on multi-walled carbon nanotubes (AuPd/MWCNT) are prepared and their application as electrochemical sensor materials for dopamine detection is explored. Furthermore, the as-prepared composite materials are identified using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray photoelectron spectrometer (XPS). In addition, the experimental results show that AuPd/MWCNT displayed excellent sensing properties to dopamine. Especially, 1% Pd-5% Au/MWCNT showed a wide detection range (0.98–200 μM) and a low detection limit of 0.058 μM for dopamine. The sensor also displayed properties such as repeatability, reproducibility, and stability, which can be ascribed to the large specific surface area and the synergistic effect of the bimetallic nanoparticles. Therefore, the prepared functionalized multi-walled carbon nanotubes have good application prospects in the field of dopamine detection.

This study used a facile method to develop a novel silver/Graphenepolypyrrole (Ag/G-PPy)-modified electrode that can be used as an electrochemical sensor for levosimendan detection. The properties of the synthesized Ag/G-PPy-modified electrode were examined through field-emission scanning electron microscopy, x-ray diffraction, and transmission electron microscopy.The Ag/G-PPy-modified electrode exhibited satisfactory current signals toward levosimendan concentrations ranging from 0.21 to 6.88 μM and exhibited a low detection limit (0.12 μM). Accordingly, the proposed electrode can serve as a simple and inexpensive electrochemical sensor for levosimendan detection.

In this study, the preparation of the composite 3% Au/graphite-C3N4 (3% Au/g-C3N4) sensing material was prepared by doping 3% Au onto the surface of graphitic carbonitride (C3N4) for detection pimobendan. By the way of sensing materials characterization, the X-ray diffraction analysis (XRD) and transmission electron Microscope (TEM) were performed. The cyclic voltammetry (CV) was used to measure the concentration and redox properties of pimobendan. It can be seen that when the voltage value is 0.05 V, and a reduction peak was appeared and the pimobendan concentration (0 to 55 μM) has a relationship with the reduction current value. At low concentrations of pimobendan concentration from 0.0 to 0.8 μM, the linearity R2 = 0.9642 with a detection limit of 0.28 μM. A possible pimobendan sensing mechanism on 3% Au/g-C3N4 was proposed.