Separation And Detection Of Typical Pollutants In Marine Environment Based On Surface Molecular Imprinting Technology

In recent years,aquaculture industry has been booming around the world,not only caused serious issue of antibiotic residues,but also brough the form of toxic red tides.Both antibiotic residues and algae toxins can bring potential toxicological effects,such as antibiotics residues could induce antimicrobial resistance in biology due to the presence of antibiotics in marine environment,and the enrichment of organisms through bioconcentration and food chain transmission could eventually cause serious damage to human health.For the purpose,to monitor and decrease the residues of antibiotics in marine environment,deserves unrelenting research attention.Due to the high salinity and complex matrix(many interfering substances,such as nutrients,organic matter,inorganic heavy metals,etc.)in marine environment and the low concentration of organic pollutant,making it difficult in detecting organic pollutants directly.Therefore,owing to the complexity of marine environment samples and the advantages of high selectivity in molecularly imprinted solid phase extraction,molecularly imprinted solid phase extraction is efficient for the separation and enrichment of target components in marine environment.Molecularly imprinted polymers possess several advantages,such as strong tolerance to the experimental environment,high mass transfer speed reusability and high adsorption capacity,which also make it an ideal choice for drug delivery system in aquaculture industry.In this paper,molecularly imprinted polymers which have specific recognition ability towards chloramphenicol,norfloxacin and gonyautoxins 2,3 in the marine environment,were prepared using surface molecularly imprinting technique based on different supporter.The corresponding analytical method was established coupling with high performance liquid chromatography for separation,enrichment and detection of typical organic pollutants in marine system.In addition,a new type of surface imprinted sustained-release microsphere was prepared using flubenicol,which is of low toxicity and high efficacy,as a drug template.A sustained-release system of flubenicol in natural seawater was constructed,which is expected to be used in actual maricultureThe primarily work and achievements of this paper are as follows:1.A straightforward method has been developed for selective separation of chloramphenicol(CAP)from marine sediment samples.Magnetic molecularly imprinted nanoparticles(MMIPs)of type Fe3O4@SiO2 were prepared via surface imprinting with CAP.The MMIPs were characterized by Fourier transform infrared spectroscopy,transmission electron microscopy and thermogravimetric analysis.They have perfect core-shell structure,excellent thermal stability,high affinity and selectivity to CAP.The imprinting factor and Scatchard analysis also reveal good specific recognition to the template.The MMIPs were applied as sorbents for fast and selective extraction of CAP from marine sediment samples.The experimental parameters affecting separation efficiency were optimized.Three marine sediment samples were analyzed.Following desorption with methanol/water(90/10,v/v),CAP was quantified by HPLC with DAD detection.The limit of detection is 0.1 μg kg-1 with a good linear response between 0.1-20 mg kg-1 of CAP concentration(R2=0.999,n=3).The method exhibits satisfactory recoveries from spiked samples(77.9-102.5%)and has low relative standard deviations(<6.3%).The magnetic material can be used at least 5 times by the regeneration without any loss of selectivity and adsorption capability.2.A simple,sensitive and effective method was developed and validated for selective adsorption and quantitation of norfloxacin(NFX)from marine sediments and seawater samples using the novel molecularly imprinted silica polymers as sorbents followed by high-performance liquid chromatographic analysis with diode array detection(HPLC-DAD).The imprinted particles were characterized by different techniques and the molecular recognition for NFX was also investigated.Several parameters affecting the extraction efficiency of molecularly imprinted solid-phase extraction(MISPE)process were optimized.Three sediment and seawater samples from Weihai bay in China were analyzed and the results show that satisfactory recoveries(77.2-98.7%)were achieved in sea-water samples with low relative standard deviation(RSD)values less than 6.89%(n=3),and the recoveries in sediments were in the range of 75.5-91.7%.The limits of detection are respectivley 2μg L-1 in seawater samples and 5 μg kg-1 in sediments.3.An innovative and effective extraction procedure based on molecular imprinting technology was developed for the isolation of gonyautoxins 2,3(GTX2,3)from seawater sample.Novel magnetic molecularly imprinted polymers(MMIPs)were prepared by double-templated imprinting strategy using caffeine and pentoxifylline as dummy templates and magnetic nanoparticles as carriers.Through evaluation of its morphology,adsorption capacity and selective recognition performance,the synthesized polymers displayed good affinity to GTX2,3 and were applied as sorbents.Further,magnetic molecularly imprinted solid-phase extraction(Mag-MISPE)protocol was optimized and an effective approach based on the Mag-MISPE coupled with HPLC-FLD was developed for selective isolation of GTX 2,3 from seawater samples.The separation method showed good extraction efficiency(78.46-89.99%)and low relative standard deviation(RSD,2.96-4.15%)for GTX2,3 and efficient removal of interferences matrices was also achieved after the Mag-MISPE process for seawater samples4.A surface molecularly imprinted drug loading system with self-made environment-friendly chitosan particles as the support and florfenicol which is widely used in aquaculture as the template molecule was established.Scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR)were used to characterize the polymer.The adsorption properties of florfenicol were also investigated by dynamic adsorption and static adsorption.In addition,in marine environmental drug release experiments evaluated that molecularly imprinted polymers have a good controlled release effect on florfenicol,and that there are still releases after 12 hours of release,with a cumulative release rate of 83.4%.Therefore,this special florfenicol drug delivery system is expected to be used in marine aquaculture with high efficacy and safety.