Electrochemical sensor for selective diquat detection based on samarium-stannate-nanoparticle-anchored titanium aluminum carbide MXene nanocomposites

The persistent presence of diquat (DQ) residue poses a significant threat to human health, underscoring the need to monitor DQ levels in agricultural samples. This is crucial for both precision and post-harvest agriculture, which require non-destructive, rapid, and cost-effective analytical methods using electrochemical detection. We developed a novel nanocomposite, composed of samarium stannate (Sm₂Sn₂O₇) nanoparticles anchored on an MXene (Ti₃Al_(1-x)C₂–OH_(x); TAC-1), for the electrochemical quantification of DQ. A three-dimensional titanium aluminum carbide MXene surface was hydroxylated and functionalized with Sm₂Sn₂O₇ nanoparticles using a combustion method. The resulting heterogeneous TAC-1-Sm₂Sn₂O₇ composite contained active sites that enabled selective and sensitive DQ detection owing to the synergistic effects of the enhanced electrocatalytic sites and rapid charge transfer. Under real-world conditions, a TAC-1-Sm₂Sn₂O₇-modified screen-printed carbon electrode sensor exhibited outstanding electrochemical activity toward DQ, with good recovery (98 %) from prepared samples. Hence, the designed sensor electrode is well suited for DQ monitoring.