Rapid preparation of CuO composite graphene for portable electrochemical sensing of sulfites based on laser etching technique

Sulfite (SO32-) is mostly used as a preservative in food products, and excessive human intake can lead to cardiac and cerebral discomfort and other adverse effects. Considering the high cost of existing SO32- detection methods and the complexity of sample handling, this study is based on laser-induced graphene technology and the simultaneous preparation of multisite copper oxide (CuO) nanoparticles and their attachment to the graphene surface, which can help to fully contact with SO32-, so as to develop a highly sensitive and consistent screen-printed electrode as an electrochemical sensor (CuO/rGO/SPE). A portable electrochemical workstation and a specially designed snap-in interface are then used for portable detection of SO32-. The structure and composition of CuO were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), etc. The electrochemical performance of the CuO/rGO/SPE sensor was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The linear response range of the electrode was 1–300 μM, the electrode sensitivity was 122.3 μAcm−2mM−1, and the detection limit was 0.2425 μM. Therefore, the CuO/rGO/SPE electrode has remarkable selectivity, stability, and reliability.