Application Of Molecularly Imprinted Membrane In The Detection Of Gonyautoxins In Seawater

Gonyautoxins 2&3（GTXs 2&3）are common carbamate-type paralytic shellfish toxins（PSP）,mainly produced by Alexandrium and other dinoflagellates.In recent years,GTXs 2&3 have been detected in several offshore areas of China.Especially in the Liaodong Bay Peninsula area,the concentration of GTXs 2&3 in fish,shrimp and shellfish has exceeded the standard for safe edible value.GTXs 2&3 can be accumulated in higher trophic organisms in marine ecosystem and potentially harm human health through the food chain,which not only affects the development of aquaculture,but also endangers food safety.In a previous study,molecularly imprinted microspheres were prepared by thermal polymerization for the detection of trace amounts of GTXs 2&3 in seawater,which was used as molecularly imprinted solid phase extraction.However,due to the resistance of seawater to flow and diffusion in chromatographic separation,the solid-phase extraction column prepared by the molecularly imprinted microbes can not obtain a good separation effect for large-volume loading.Molecularly imprinted membranes were prepared in order to solve this problem in this study.Compared with molecularly imprinted microspheres,molecularly imprinted membrane chromatography is beneficial to obtain a higher flow rate and improve the separation speed when the bed volume is constant.The flow diffusion resistance is eliminated and the transfer effect is greatly improved.This paper studies in the following areas.1.In this study,polyvinylidene fluoride（PVDF）membrane was used as the base membrane to prepare molecularly imprinted composite membranes by thermal polymerization,and the performance and structure characterization,kinetic and thermodynamic studies of the molecularly imprinted composite membranes were conducted.The characterization results showed that the method achieved the chemical binding of the molecularly imprinted microsphere to the basal membrane and had good stability.The adsorption of GTXs 2&3 was a monolayer adsorption with a high adsorption capacity.2.The molecularly imprinted membranes were made of filler and used for solid phase extraction.The conditions of solid phase extraction were optimized,and detection limit,accuracy and column reproducibility were determinedf.The results showed that a good separation effect was performed when the mixture of molecularly imprinted plate membranes and microspheres was used as SPE column filler for sample pretreatment.The detection limit of GTXs 2&3 was 0.230μg·L^-1,and the detection limit of samples was 0.137μg·L^-1.A good intraday and interday precision was also showed.3.Alexandrium tamarense,a kind of representative algae species caused harmful algae blooms and secreted GTXs 2&3 in coastal area of China,was used as research object.A.tamarense were cultured and the growth density and secretion of toxins were observed in a 30-day growth cycle.The results showed that GTXs 2&3 were detected in A.tamarense at different growth stages.The concentration in exponential phase was 4.362μg·L^-1and that in stable phase was 9.066μg·L^-1.