ZIF-67 based CoS self-assembled on graphitic carbon nitride microtubular for sensitive electrochemical detection of paraquat in fruits.

Paraquat (PQ) is a widely used and harmful herbicide that must be detected in the environment. This study reports a novel composite (CoS-GCN) prepared by assembling cobalt disulfide (CoS) derived from metal-organic frameworks (MOFs) on graphitic carbon nitride (GCN). An electrochemical sensor (CoS-GCN/ glassy carbon electrode (GCE)) was successfully prepared by modifying CoS-GCN onto a GCE to sensitively detect PQ. Different concentrations of PQ were detected using square-wave voltammetry, and the CoS-GCN/GCE electrochemical sensor showed remarkable response signals for PQ in the range of 20 - 1000 nM and 1 - 13 μM, with a detection limit of 4.13 nM (S/N = 3). The CoS-GCN/GCE electrochemical sensor exhibited high stability, reproducibility, and immunity to interference, which were attributed to the synergistic effects of CoS and GCN. In addition, the CoS-GCN/GCE electrochemical sensor showed high applicability for the analysis of fruit samples. Therefore, the proposed sensor has potential applications in PQ detection.