Molecularly Imprinted Electrochemical Sensor Based on MWCNTs/GQDs for the Detection of Sulfamethazine in Aquaculture Seawater

In this work, a novel molecularly imprinted electrochemical sensor was proposed based on molecular imprinting technology for the detection of sulfamethazine. A glassy carbon electrode was modified with a composite material of carbon nanotubes and graphene quantum dots to effectively improve sensitivity. The molecularly imprinted electrochemical sensor was then prepared by electropolymerization using sulfamethazine as the template and o-phenylenediamine as the functional monomer on the modified electrode. Under optimal measurement conditions, electrochemical tests of different sulfamethazine concentrations (0.5 μM–200 μM) showed excellent linearity and a detection limit of 0.068 μM. In addition, the sensor demonstrated satisfactory selectivity, stability, and reusability. Furthermore, the sensor was applied to the spiked analysis of sulfamethazine in grouper aquaculture water, achieving recovery rates between 95.4% and 104.8%, with a relative standard deviation (RSD) of less than 4.14%. These results indicated that the developed method was effective for the analysis of sulfamethazine in aquaculture seawater, providing a new approach for the detection of antibiotic residues in seawater samples.