| The rapid development of aquaculture has increased the content of antibiotics in the water environment,causing serious harm to the surrounding plants and animals.The monitoring of drugs in the environment is helpful to maintain the stability of the ecosystem,while the content of drugs in the wastewater is very low,so it is necessary to find a method for sample pretreatment.With the rapid development of life science and technology,nucleic acid,as the core of life,is widely used in gene detection,gene diagnosis,gene therapy and so on.Nucleic acid and protein are often combined to function,so it is necessary to separate nucleic acid to meet the biological requirements.Liquid-liquid extraction（LLE）technology is a common sample separation method,which can not only improve the separation purity of target molecules,but also obtain a high recovery rate.However,the LLE method requires a large amount of organic solvent,requires multiple centrifugations,and the operation is complicated.The emergence of solid phase extraction（SPE）technology has solved these problems,and it is easy to realize automatic operation.However,in traditional SPE technology,the extraction column is prone to blockage when a large number of samples are separated,requiring a pressurized operation or frequently replacing the separation medium,which take a long time.The magnetic solid phase extraction（MSPE）technology uses magnetic particles as adsorbents without filling them into the extraction column,which effectively solves the problems of easy blockage and long separation time of the extraction column,and has all the advantages of traditional SPE technology.The ideal magnetic medium should have uniform particle size,high saturation magnetization,superparamagnetic and high mechanical strength,so as to achieve controllability,high efficiency and repeatability of MSPE.This paper is dedicated to prepare a series of new magnetic microspheres as MSPE fillers,which is used to adsorb drugs and nucleic acid.In view of the above requirements,the research objective of this paper is to prepare a highly responsive monodisperse magnetic microsphere for the enrichment of drugs in wastewater and nucleic acid isolation.Based on these,this paper can be divided into the following three parts:In the first part,magnetic porous silica（MPS）microspheres were prepared.Firstly,the monodisperse silica microspheres were prepared by template method.The prepolymer was deposited many times,which improved the bulk density of silica microspheres and formed the macroporous structure in the microspheres.The magnetic nanoparticles were used to coat MPS microspheres.The macroporous structure was favorable for the deposition of magnetic particles and enhanced the magnetic response of MPS microspheres.After characterization,the results showed that the MPS microspheres prepared by this method had controllable particle size,regular spherical shape,good dispersion and high magnetic response.In the second part,the MPS microspheres were used as adsorbents and the hydrophobic functional groups were coated on the surface to enrich the cephalosporins in wastewater.In this experiment,the type and extraction conditions of MPS microspheres were optimized and successfully applied to the enrichment of cephalosporins in different wastewater,the recovery rates were all above 86%.In the third part,MPS microspheres were used as adsorbents to coat the surface with hydrophilic groups to separate and purify nucleic acid molecules from different biological tissues.Under the optimized conditions,DNA molecules with A260/A280ratio between 1.8-2.0 and high molecular weight were successfully extracted from calf thymus,green pepper seeds and Escherichia coli.In summary,this paper successfully prepared highly responsive monodisperse MPS microspheres and applied them to the separation and extraction of antibiotics in wastewater,then applied them to the separation and purification of nucleic acid molecules in different tissue samples,achieved good separation and enrichment effect. |
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