A novel ratiometric molecularly imprinted electrochemical sensor based on Ag and ionic liquid co-functionalized MXene for highly sensitive and selective detection of patulin

Herein, a novel ratiometric molecularly imprinted electrochemical sensor (MIP-RECS) based on Ag nanoparticles (AgNPs) and ionic liquid (IL) co-modified Ti₂NTx (AgNPs@Ti₂NT_x@IL) was developed for the determination of patulin (PAT). Firstly, the AgNPs@Ti₂NT_x@IL nanocomposite, was prepared by an in situ reduction and self-assembled method, and then, was cast on the glassy carbon electrode (GCE) to build an electrochemical interface with excellent conductivity and high surface area. After that, the MIP was deposited on the nanocomposite modified GCE by the electro-polymerization technique, with thionine (Thi) and PAT as functional monomer and template molecules. In the sensing platform, the oxidation peaks generated by Thi and AgNPs were used as reference and probe signal, respectively. The introduction of reference effectively eliminates the influence of the matrix effect. At the same time, the oxidation signal of the Ag probe is greatly improved by the high conductivity and large surface area of the AgNPs@Ti₂NT_x@IL nanocomposite. Therefore, the MIP-RECS presented a wide linear range, a very low low limit of detection (LOD), together with high selectivity and excellent repeatability. Additionally, the linearity ranges and LODs of the sensor can be controlled by the amount of Ag, highlighting its robustness in different types of real samples. Furthermore, this sensing model can be used to sensitively detect other residues with poor redox activity, such as imidacloprid and catechol, highlighting its versatility and universality.