Preparation of core-shell magnetic molecularly imprinted polymers on Fe3O4 nanosphere via self-polycondensation for magnetic solid-phase extraction of 2,4-dinitrophenol in environmental water samples

In this study, a core-shell magnetic molecularly imprinted polymers (MMIPs) adsorbent targeting 2,4-dinitrophenol (2,4-DNP) as a template molecule was developed by surface polymerisation and applied for magnetic solid-phase extraction prior to the determination of 2,4-DNP in environmental water samples via high-performance liquid chromatography. Different experiments were carried out to optimise the magnetic solid-phase extraction conditions. Subsequently, the adsorption capacity and selectivity of prepared MMIPs were investigated. Theoretical analysis demonstrated that the experimental data fitted well to the pseudo-second-order model, suggesting that chemical adsorption might be the rate-limiting step, with a maximum adsorption capacity of 21.76 mg g−1. Under the optimised conditions, this method showed relatively wide linearity within the concentration range of 0.0025 μg·mL−1−0.5 μg·mL−1, with a relative standard deviation of 2.5%–6.2%. The detection limit and quantification limit were 0.23 µg·L−1 and 0.76 µg·L−1, respectively.