Abstract: A molecularly imprinted electrochemical sensor for the detection of sulfadiazine was prepared using sulfadiazine as a template molecule and o-aminophenol as a functional monomer at an optimized ratio as determined by UV spectroscopy. The glassy carbon electrode was modified by drop casting method with carbonylated multi-walled carbon nanotubes and nano-gold sol. Poly (o-aminophenol) membrane was formed by electropolymerization in perchloric acid-sodium perchlorate solution (pH 5.5). In the experiment, an aqueous solution containing 0.5 mol/L KCl and 5 mmol/L K3[Fe(CN)6] was used for the characterization of the sensor. The response characteristics of the electrochemical sensor were evaluated by cyclic voltammetry and differential pulse voltammetry. The preparation conditions were optimized. The selective response of the sensor to the template molecule and its analogues was investigated. It was applied to the rapid detection of sulfadiazine residues in foods. The results showed that under the optimum conditions, good linearity was observed in the concentration range of 1.0 × 10-8–2.0 × 10-6 mol/L. The limit of detection (LOD) was 3.3 × 10-9 mol/L, and the average recoveries from spiked samples were between 83.50% and 97.80%, with relative standard deviations (RSDs) less than or equal to 4.0%. The sensor is very promising due to its low cost, easy and rapid operation, high sensitivity, strong interference resistance and good stability.

Key words: sulfadiazine, electrode modification material, molecularly imprinted polymer, electrochemical sensor, UV spectroscopy