Ratiometric electrochemical sensor based on methylene blue-functionalized Ti3C2Tx MXene/Pt nanoparticle composites for reliable detection of carbendazim

Abstract

Rapid and reliable detection of pesticide residues is critical in public health, food safety and environmental control. Herein, a novel ratiometric electrochemical sensor based on methylene blue-functionalized Ti₃C₂T_x MXene/Pt nanoparticle composites (MXene@MB/PtNPs) was developed for reliable detection of carbendazim (CBZ). The MXene@MB/PtNPs composites were synthesized by a mild and simple room-temperature approach. Here, the decoration of Pt nanoparticles can enhance the conductivity and catalytic activity of the composites. The functional electroactive molecule methylene blue (MB) implanted in MXene could not only hinder the aggregation of MXene layers and promote the electron transfer activity of the materials, but also serve as an internal reference probe to form a ratiometric sensing strategy. The obtained MXene@MB/PtNPs composites showed a superior electrochemical catalytic performance toward CBZ. Based on the ratiometric signal of the response current to the reference current (I_CBZ/I_MB), the developed sensor possessed a wide linear range of 10 ng mL^-1 to 30 μg mL^-1 with a low LOD of 4.2 ng mL^-1. Compared with single-signal detection, the developed ratiometric electrochemical sensor could offer more accurate and reliable results, and exhibited favorable selectivity, reproducibility and long-term stability, and great application potential in pesticide residue detection in agricultural products.