A biosensor based on hemoglobin immobilized with magnetic molecularly imprinted nanoparticles and modified on a magnetic electrode for direct electrochemical determination of 3-chloro-1, 2-propandiol

A biosensor for determination of 3-chloro-1, 2-propandiol (3-MCPD) was developed based on the electrochemically catalytic reduction by hemoglobin (Hb). Hb was concentrated and immobilized with magnetic molecularly imprinted nanoparticles (MMIPs NPs). The MMIP NPs had a core-shell structure, with magnetic Fe 3 O 4 NPs as the core and SiO 2 as the shell. MMIPs NPs were modified on the surface of a magnetic electrode to constitute the Hb enzyme-like sensor. The biosensor could catalyze the electrochemical reduction of 3-MCPD, and a direct electrochemical determination of 3-MCPD could be achieved for the first time. The biosensor, where Hb immobilized with MMIPs NPs had high electrochemical response for 3-MCPD, increased by 37.5% compared with Hb immobilized with magnetic non-imprinted nanoparticle (MNIPs NPs). The biosensor increased the response by 19.56% again under an external magnetic field . The reduction peak current had a linear relationship with 3-MCPD concentration ranging from 1.0   mg·L −1 to 160   mg·L −1 with a detection limit (S/N   =   3) of 0.25   mg·L −1 . The biosensor was applied to the determination of 3-MCPD in soy sauce samples successfully with recoveries between 97.4% and 99.6%.