Constructing magnetically functionalized sandwich-like Eu-MOF/PDA@MXene hybrids for extremely sensitive molecular imprinted sensor toward trace detecting trimethylamine oxide

MXene is prone to aggregation during electrode preparation, which hinders the transmission of electrons and limits its application in sensors. In this study, a novel multilayered sandwich-like Eu-MOF/PDA@MXene was in-situ synthesized from Eu3+ with ternary mixed ligands of 1,3,5-benzenetricarboxylic acid, terephthalic acid and polydopamine-modified MXene (PDA@MXene), and analyzed via scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Moreover, the excellent electrochemical performance was recorded via electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Due to the multilayered and porous structure of Eu-MOF/PDA@MXene, Fe3O4 nanoparticles can be uniformly fixed in Eu-MOF/PDA@MXene by self-assembly, which not only enables magnetic functionalization of the material but also significantly improves the electrocatalytic performance of the material. Furthermore, combined with molecularly imprinted polymer (MIP), MIP/Eu-MOF/PDA@MXene/Fe3O4/MGCE (magnetic glassy carbon electrode) electrochemical sensor was built for detecting ultratrace trimethylamine oxide (TMAO), which had high selectivity and sensitivity. In the concentration range of 9 × 10-15 − 9 × 10-18 mol/L, the relationship between differential pulse voltammetry (DPV) response and logarithm of TMAO concentration was linear with a detection limit of 1.25 × 10-18 mol/L. In addition, this MIP sensor had superior recoveries in real sample detection of urine and plasma.