Ultrasensitive determination of diquat using a novel nanohybrid sensor based on Super-P nanoparticles dispersed palygorskite nanofibers

The excessive diquat (DQ) residue poses a serious hazard to the ecological environment and human health. Herein, a simple, low-cost, and scalable ultrasonication-assisted strategy was proposed to fabricate the composite of Super-P carbon black nanoparticles dispersed palygorskite (Pal) nanofiber, which was employed to construct an electrochemical sensor for DQ determination. The Pal/Super-P/GCE sensor exhibited ultrasensitive determination performance with a low detection limit (0.1514 nM) and high sensitivity (44.141 μA μM−1) in the linear DQ concentration range of 0.00050–1.0 μM. The recoveries of the constructed sensor ranged from 95.6 % to 100.3 % when applied to detect DQ in river water, potato, and cucumber. The above enhanced DQ detection performance was primarily due to the synergistic effect of Pal and Super-P. Pal with high adsorption ability and excellent biocompatibility could provide numerous attachment sites for DQ adsorption due to the superior ion-exchange property and plentiful Si-OH on its surface. Super-P with pearl-chain like structure contributed to forming an interconnected conductive network, thus facilitating the homogeneous dispersion of Pal and compensated for the poor conductivity of Pal. This study provides a valuable reference in developing clay-based nanocomposite via ultrasonication-assisted strategy to achieve the application of electrochemical sensor at the ultra-trace levels detection of pesticides.