Molecularly imprinted ratiometric electrochemical sensor based on 3D-1D MoS2@CNTs hetero-nanoflower for selective detection of trimethoprim

Trimethoprim (TMP) is a broad-spectrum antibiotic that is frequently found residue in the environment and food. An innovative electrochemical sensor was proposed for the detection of trimethoprim with high selectivity, sensitivity and reproducibility through the integration of the flower-like MoS2@CNTs heterostructure as substrate, molecular imprinted polymer (MIP) technology as recognition, and the ratiometric strategy between trimethoprim and ferrocene (Fc) for quantitative. The recognition reaction of TMP by MIP-MoS2@CNTs sensor was assumed as an irreversible electrochemical oxidation reaction controlled by a combination of adsorption-diffusion process with two electrons and protons. With the incorporation of Fc during detection, a satisfying linear relationship of ITMP/IFc and the concentration of TMP was achieved, indicating a detection concentration ranging from 50 to 3000 nmol·L−1 with a detection limit of 27.01 nmol·L−1. In addition, the MoS2@CNTs MIP ratiometric sensor exhibited good stability for 20 days and excellent reproducibility with a relative standard deviation of 1.06 %, which was lower than 3.89 % of single signal. The practical feasibility of the sensor was detected in water samples with recovery rates of 98.62 ∼ 107.47 % and fish samples with recovery rates of 98.93 ∼ 105.45 %. Overall, the developed MIP ratiometric sensor provides a versatile system with easy operation and great potential for detecting small hazardous molecules in the environment and food products.