Fabrication of an oxytetracycline molecular-imprinted sensor based on the competition reaction via a GOD-enzymatic amplifier

A highly sensitive molecular-imprinted polymer sensor (MIP sensor) for ultratrace oxytetracycline (OTC) determination was prepared based on the competition reaction between template molecule OTC and glucose oxidase (GOD)-labeled OTC (GOD-OTC). Sensitivity improved dramatically due to the detection of a huge amount of enzyme catalytic production, which was inversely proportional to template molecule concentration. The MIP sensor was characterized by alternating current impedance spectroscopy and cyclic voltammetry, and its voltammetric behavior was also verified. Experimental conditions including isolation, incubation, and competition were optimized. OTC can be determined at concentrations between 0 and 4.0 × 10−7 mol/L with a detection limit of 3.30 × 10−10 mol/L by the differential pulse voltammetry technique. The MIP sensor showed high sensitivity, selectivity, reproducibility, and good recovery in sample determination.