Highly Sensitive Molecularly Imprinted Electrochemical Sensor Based on the Double Amplification by an Inorganic Prussian Blue Catalytic Polymer and the Enzymatic Effect of Glucose Oxidase

A novel strategy to improve the sensitivity of molecularly imprinted polymer (MIP) sensors was proposed. An electrocatalytic Prussian blue (PB) film was electrochemically polymerized on an electrode surface to fabricate an MIP electrochemical sensor using oxytetracycline (OTC) as a template. The OTC determination relied on a competition reaction between OTC and glucose-oxidase-labeled OTC and the catalytic reduction of hydrogen peroxide by the modified PB film. Experimental results show that double amplification, which is based on the catalysis of inorganic PB films and the enzymatic effect of glucose oxidase, can remarkably increase the assay sensitivity. The main experimental conditions (including electrocatalysis of the PB film, pH effects, incubation and competition times, and anti-interference) were optimized. This novel MIP sensor can offer an femtomole detection limit for OTC. In addition, the feasibility of its practical applications has been demonstrated in the analysis of a series of real milk samples.