| Over the past few decades,manufacturing and aquaculture have boomed.The unreasonable disposal of waste water and waste has caused organic pollution of natural environment especially marine environment.More and more attention has been paid to the detection of various organic pollutants in marine environment.Marine environmental substrate is relatively complex,with high salinity,more interference impurities and low pollutant content,which makes the detection of organic pollutants more difficult.Molecularly imprinted polymers(MIPs)have the advantages of predication,selective recognition and practicability.The combination of molecular imprinting technology(MIT)and fluorescence spectrophotometry is expected to be used for the efficient analysis and determination of organic pollutants in seawater or sediment samples.In this study,rhodamine B(RhB)and okadaic acid(OA),which are emerging organic pollutants in the marine environment,were selected as the research objects.Using magnetic Fe3O4@SiO2 as the carrier,molecularly imprinted solid-phase extraction adsorbent and nano fluorescent probe were prepared by precipitation polymerization and sol-gel method respectively.Rapid and sensitive analysis of target pollutants was realized by magnetic molecular imprinting technique combined with fluorescence analysis.The main research contents and results of this paper are as follows:1.A highly efficient sample clean-up and preconcentration using novel magnetic molecularly imprinted polymers(MMIPs)as adsorbents 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.After solid-phase extraction under optimal conditions,the fluorescence analysis of RhB showed a wide linear response between the concentration range of 2.5～112.5 μg L-1 and the fluorescence intensity at 576 nm,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.2.A sensitive fluorescence quenched magnetic molecularly imprinted nanoprobe was developed based on the virtual template strategy.The specific recognition and rapid detection of OA in marine sediment samples were realized by fluorescence spectrum analysis.In the preparation of MMIPs,monenamycin sodium was used as the virtual template and 7-hydroxy-coumarin was embedded as the fluorescence signal response.The synthesized MMIPs showed strong blue fluorescence emission at 380 nm excitation.During the selective adsorption process,the fluorescence intensity of the probe was effectively quenched.The relative fluorescence intensity of the probe showed a good linear relationship with OA concentration in the range of 75.6～982.8 ng L-1,with a low detection limit(22.7 ng L-1).The OA recovery rate of the spiked sediment samples ranged from 90.75%to 95.41%,with relative standard deviation less than 4.64%(n=3).This molecularly imprinted fluorescent probe has high molecular recognition ability,good stability,and anti-interference ability.And it can be used for rapid detection of OA in marine sediments. |
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