Fluorescence assay of oxytetracycline in seawater after selective capture using magnetic molecularly imprinted nanoparticles

A comprehensive strategy for manufacturing a novel sorbent based on magnetic molecularly imprinted polymers (MMIPs) is addressed for selective capture of oxytetracycline from seawater. The novel MMIPs were synthesized by nano-Fe3O4 as sacrificial matrix and adsorption properties of the polymers demonstrate rapid adsorption kinetics, high adsorption capacity, and specificity towards oxytetracycline provided by the core-shell composite structure. After screening the critical parameters by multivariate optimization, a magnetic imprinting solid phase extraction method combined with fluorescence spectrophotometry (MMIP-SPE-FL) was constructed for sensitive determination of oxytetracycline in seawater samples. The results show a good linear response dependence on the spiking concentration of 3–100 μg L−1, and a satisfactory limit of detection of 0.7 μg L−1 after the MMIP-SPE preconcentration. Seven seawater samples from Jiaozhou bay were analyzed to give recoveries in the range of 89.75–107.65% with relative standard deviation values of less than 5.44% (n = 3).