Multivariate optimization of magnetic molecular imprinting solid-phase extraction to entrap rhodamine B in seawater

Abstract

A highly efficient sample clean-up and preconcentration using novel magnetic molecularly imprinted polymers (MMIPs) as dispersant sorbents was developed for selective entrapment and rapid detection of rhodamine B from seawater samples coupled with fluorescence spectrometry. The MMIPs were synthesized by surface imprinting technique employing nano-Fe3O4 particles as carriers and rhodamine B as template molecule. The characterizations of prepared nanocomposites were fully investigated and molecular recognition assays exhibited high affinity and selectivity for rhodamine B. As magnetic adsorbents, several essential factors that affecting extraction efficiency during sample preparation were systematically optimized via response surface methodology with Box–Behnken design. Under optimum conditions, the proposed method presented a wide linear response over the concentration range of 2.5 ∼ 112.5 μg L−1, with a limit of detection (LOD) of 0.45 μg L−1. Finally, five seawater samples collected from Jiaozhou Bay were analysed and the recoveries of the spiked samples were found from 94.90 to 102.48% with relative standard deviations lower than 5.36% (n = 3). The results show that the developed method could be considered as an attractive and sensitive alternative for rapid analysis of organic dyes at trace levels in complex seawater matrix.