A Sensitive and Selective Electrochemical Sensor for Sulfadimethoxine Based on Electropolymerized Molecularly Imprinted Poly (o-aminophenol) Film

Background: As a broad-spectrum antibiotic of the sulfonamide family, Sulfadimethoxine (SDM) has been widely utilized for therapeutic and growth-promoting purposes in animals. However, the use of SDM can cause residual problems. Even a low concentration of SDM in the aquatic system can exert toxic effects on target organisms and green algae. Therefore, the quantitation of SDM residues has become an important task. Methods: The present work describes the development of a sensitive and selective electrochemical sensor for sulfadimethoxine based on molecularly imprinted poly(o-aminophenol) film. The molecular imprinted polymer film was fabricated by electropolymerizing o-aminophenol in the presence of SDM after depositing carboxylfunctionalized multi-walled carbon nanotubes onto a glassy carbon electrode surface. SDM can be quickly removed by electrochemical methods. The imprinted polymer film was characterized by cyclic voltammetry, differential pulse voltammetry and scanning electron microscopy. Results: Under the selected optimal conditions, the molecularly imprinted sensor shows a linear range from 1.0 x 10-7 to 2.0 x 10-5 mol L-1 for SDM, with a detection limit of 4.0 x 10-8 mol L-1. The sensor was applied to the determination of SDM in aquaculture water samples successfully, with the recoveries ranging from 95% to 106%. Conclusion: The proposed sensor exhibited a high degree of selectivity for SDM in comparison to other structurally similar molecules, along with long-term stability, good reproducibility and excellent regeneration capacity. The sensor may offer a feasible strategy for the analysis of SDM in aquaculture water samples.