Surface Imprinting Materials For The Detection Of Doxycycline And Acetamidine In Marine Environmental Samples

At present,marine environmental pollution is becoming more and more severe,including the residue caused by the excessive use of antibiotics in aquaculture and the widespread use of neonicotinoid pesticides as substitutes for organophosphorus and other pesticides.These emerging organic pollutants will eventually accumulate in the marine environment and continue to bioaccumulate through the food chain,posing a potential threat to human health.Due to the complex background matrix of marine environment,many interfering substances,high salinity,and low content of objects to be measured,the quantitative analysis process of target substances is difficult.Therefore,it is necessary to design efficient and sensitive analysis and detection methods for typical emerging pollutants in marine environmental samples(including seawater and sediments).Molecularly imprinted polymers have the advantages of specific identification of target substances,high stability and easy preparation,and are widely used in the fields of solid phase extraction,chromatographic separation and sensing analysis.In this paper,tetracycline,doxycycline,and neonicotinoid pesticide,acetamidine,which are emerging pollutants in the environment,are selected as the research object.Using Fe3O4 and SiO2 nanoparticles as support carriers,core-shell imprinted nanomaterials are prepared by surface imprinting technology.A highly selective magnetic imprinted adsorbent with a sensitive magnetic response and a silicon-based imprinted fluorescent probe with a fluorescence response were developed for the rapid and sensitive detection of doxycycline and acetamidine in marine sediments and natural seawater samples by high performance liquid chromatography and fluorescence spectrometry.The main contents and results of the paper are as follows:1.A rapid and sensitive trace analysis method for doxycycline in marine sediment samples was designed.Fe3O4@SiO2(nuclear support matrix)was obtained by coprecipitation and sol-gel method.The magnetic imprinted nanomaterials with specific doxycycline adsorption were constructed by surface imprinting method.A multi-variable method based on Box-Behnken response surface method was designed to optimize the selection of key parameters of MMIP-SPE,including adsorption dose and type of eluting solvent.A new sensitive method for the detection of doxycycline in marine sediment samples was established by magnetic imprinting dispersion solid phase extraction and high performance liquid chromatography(MMIP-SPE-HPLC).Under the optimal conditions,the detection limit was 0.03 μg-1,the linear range was 0.5-20 μg-1,the recoveries were 90.60-93.76%,and the relative standard deviations were less than 4.12%.The method developed in this experiment is supported by magnetic base carrier,avoids complicated filtration or centrifugation steps,and is simple to operate.It can efficiently extract,enrich and detect doxycycline in complex marine environment matrix,and has good applicability.2.Based on the photoinduced electron transfer(PET)mechanism,the organic fluorescent dye fluorescin isothiocyanate(FITC)was used as the fluorescence response element,modified by APTES active agent and grafted onto the surface of nano-SiO2.A fluorescence enhanced silicon-based imprinted fluorescent probe SiO2@FITC@MIPs was prepared by precipitation polymerization.For the specific recognition of acetamidine.In this experiment,the identification performance of the fluorescent probe was systematically studied,and the key parameters of the detection system were optimized.The results showed that the probe could be specifically identified with acetamidine,and the fluorescence intensity of FITC was enhanced rapidly and linearly in the range of 0～45 μg L-1.The detection limit of FITC was as low as 1.5 μg L-1,and the recovery rate was 96.84-103.46%.The relative standard deviation is less than 5.18%(n=3).The molecularly imprinted fluorescent probe achieves a combination of high selectivity and signal transmission performance.This simple and sensitive sensor analysis strategy has great potential for specific identification and rapid determination of trace acetamidine in complex marine environments.