A stimuli response, core-shell structured and surface molecularly imprinted polymers with specific pH for rapid and selective detection of sulfamethoxazole from milk sample

In this study, a novel kind of pH-responsive, magnetic and core-shell structured molecularly imprinted polymer (pH-MMIPs) was synthesized for the selective recognition of sulfamethoxazole (SMX). It was synthesized by way of surface imprinting and free radical polymerization. The composition and structure of pH-MMIPs has magnetic nanoparticles as its core, a thin imprinted polymer layer as its shell using 2-(Dimethylamino) ethyl methacrylate and 4-vinylphenylbronic acid as the pH-sensitive monomers, and SMX as template molecule. Interestingly, the pH-MMIPs could control the capture/release process in the selective recognition and detection of SMX by changing the pH value. Evaluation of the property of pH-MMIPs through series of adsorption experiments showed that it has an adsorption capacity of 25.41 mg·g−1 with a very rapid speed of magnetic separation. Additionally, it was successfully applied to selectively detect SMX in real milk samples, and the recoveries was in ranges of 89.7% and 98.2%. This study provides a new method and idea for the selective separation of SMX residue in food using molecularly imprinted polymers with pH- response and identification.