Molecularly imprinted electrochemical sensor based on terthiophene-covalent organic frameworks and MXene hybrid synergies for ultra-trace detection of trimethoprim in food samples

The sensing performance of molecularly imprinted polymer (MIP) electrochemical sensors is restricted by the poor conductivity of MIP. Modifying electrodes with nanomaterials with good conductivity is a feasible method to improve the sensitivity of MIP electrochemical sensors. Herein, an MIP/TTA-TAPE-COF/MXene/GCE electrochemical sensor is constructed using novel layered pastry-like terthiophene-covalent organic frameworks (TTA-TAPE-COF) and MXene hybrids as modifying electrode materials and combined with MIP. Its outstanding electrochemical performance is demonstrated through electrochemical impedance spectroscopy (EIS) as well as cyclic voltammetry (CV). Further, the fabricated MIP/TTA-TAPE-COF/MXene/GCE sensor is applied for detecting ultra-trace trimethoprim (TMP), which has high specificity and sensitivity. The response of the differential pulse voltammetry (DPV) is linearly related to the logarithm of TMP concentration within the range of 9 × 10 −15 –9 × 10 −18  mol L −1 . The detection limit is 6.48 × 10 −18  mol L −1 . Besides, the method has an outstanding recovery in food sample analysis. The hybrid of COFs and MXene can prevent MXene from self-restacking and improve its electrical conductivity. Thus, this method markedly enhances the sensing performance, and it will provide a detection platform for ultra-trace detection of organic amine.