A rapid and recyclable analysis method for sulfadimethoxine detection based on molecularly imprinted electrochemical sensor reinforced by GQDs/ZIF-8 nanocomposite

An ultrasensitive molecularly imprinted polymeric (MIP) sensor for rapid and specific detection of sulfadimethoxine (SDM) in milk and water samples was developed in this research. The proposed MIP sensor construction process was based on the drop-casting of GQDs on a glassy carbon electrode and electro-polymerization of novel zeolitic imidazolate framework-8 (ZIF-8) with SDM as template and aniline as monomer. GQDs with excellent conductivity and ZIF-8 with porous structure showed a synergistic effect on promoting electron transfer and increasing the number of binding sites, thereby providing high sensitivity for SDM detection. Under optimal conditions, the sensor showed two dynamic ranges from 0.01 to 1.0 nM and 1.0 to 275 nM with a detection limit of 0.0063 nM. The accuracy and precision of the proposed platform was studied in real samples for four concentration levels and the recoveries were obtained from 96.3 to 107 % with RSD values of 1.87 to 4.11 % (n = 3).