Electrochemical determination of tetracycline using AuNP-coated molecularly imprinted overoxidized polypyrrole sensing interface

Highlights: • Screen-printed electrodes were modified with molecularly imprinted overoxidized polypyrrole to detect tetracycline. • The application of sodium dodecyl sulfate improved current response to target analyte. • Enhanced sensitivity and selectivity towards tetracycline in the presence of various interferents was attained. • Tetracycline in real food sample was successfully detected with recovery percentage comparable to LC-MS assay. A selective and sensitive electrochemical sensor was developed for tetracycline (TC) detection based on low cost screen-printed carbon electrodes (SPCE) modified with molecularly imprinted overoxidized polypyrrole (MIOPPy) and gold nanoparticles (AuNP). Molecularly imprinted polypyrrole (MIPPy) was prepared by electropolymerization of pyrrole in the presence of TC molecules as templates. The removal of templates was achieved by overoxidation in the presence of 0.05 mol dm⁻³ NaOH. Electrochemical behavior of TC on MIOPPy-AuNP/SPCE was studied using differential pulse voltammetry (DPV) in the presence of sodium dodecyl sulfate. The sensor showed good selectivity against common antibiotics used in agriculture, namely, chloramphenicol and amoxicillin. Under optimized conditions, the calibration curve exhibited linear trend from 1 to 20 μmol dm⁻³ with limit of detection of 0.65 μmol dm⁻³. The sensor was successfully used to determine TC in real food samples with recovery percentage above 90%, comparable to LC-MS assay. The proposed approach was versatile and could be readily modified to detect other contaminants in foods and environment.