Electrochemical sensor based on molecularly imprinted polymer and voltammetric electronic tongue technology: an efficient strategy for sensitive detection of tobramycin residues

Tobramycin (TOB) is an aminoglycoside antibiotic widely used to treat chronic lung infections and other bacterial diseases. However, TOB residues may persist in food products derived from animals treated with antibiotics, posing a risk of promoting antibiotic resistance in consumers. This highlights the urgent need for sensitive and selective methods to detect TOB residues in food. In this study, both an electrochemical sensor based on a conductive molecularly imprinted polymer (MIP) and a voltammetric electronic tongue (VET) system were developed for the detection of TOB. The MIP sensor was fabricated by electropolymerizing polyaniline onto a screen-printed gold electrode (Au-SPE), with the sensitivity further enhanced by the incorporation of silver nanoparticles. Surface morphology characterization of the modified electrodes was carried out using scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR). Cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) were employed to characterize the sensors during both their fabrication and the TOB detection process. The sensors exhibited a detection limit of 1.9 pg mL^-1 within a concentration range of 0.001-60 pg mL^-1. The MIP sensors were selective for TOB, and were successfully applied to the detection of TOB residues in various food samples, including chicken, beef, turkey, chicken eggs, and milk. The VET system combined with chemometric methods particularly demonstrated its effectiveness in detecting TOB in milk samples. Principal component analysis (PCA) and discriminant function analysis (DFA) confirmed the ability of the VET system to differentiate between TOB-contaminated and uncontaminated milk samples, with PCA explaining 96.94% of the variance. This study presents a significant advance in the electrochemical detection of antibiotics in food, demonstrating the potential of MIP-based sensors, VET system for practical applications in food safety monitoring, and public health analysis.