Preparation Of Molecularly Imprinted Coatings By Sandwich Method Based On Support Membrane And Its Application In 2,4-D Analysis

The polymer coating was prepared by a novel sandwich method which based on functionalized glass slide as substrate and micropore membrane as support material polymer carrier,respectively,with controllable thickness and in-situ chemical grafting.The experimental results demonstrated that the method has characteristics of feasibility,and good reproducibility and reliability.And the polymer coating exhibited advantages,such as good stability,repeatability,robustness,uniformness as well as relatively smooth surface and so on.The application on the basis of optimized polymer coatings were further developed and applied in visual colorimetric tests,in-situ fluorescence imaging,molecular imprinting,in-situ fluorescence analysis and detection as well as in-situ mass spectrometry imaging.The study will further provide new strategies and thoughts for coating preparation method and wide application,and also has important guiding significance and reference value in preparing coating of sensors or solid phase microextraction,sample pretreatment and in-situ analysis and detection in the future.Moreover,the coating exhibits a wide range of potential applications prospects and values,such as environmental analysis,food safety,diagnosis and analysis of diseases,drug screening and analysis and scientific research.The novel sandwich method was reasonably developed to prepare polymer coating dependent on the functionalized substrate and support membrane,which method was inspired by the sandwich method and the surface modification functional group of substrate to prepare the coating or film.Firstly,the method was verified by preparing the same or different compositions of polymer coating,and performing on adsorption or desorption experiments of coating for different auxin.The results indicated that the method is feasible,reliable and has good reproducibility and reusability.On the basis of above results,it was investigated by ultrasonic,acid-base and organic solvent soaking experiments for a long time,the coating exhibited better stability and firmness based on this method.Finally,the controllable thickness of the polymer coating was verified by a support membrane of the same or different composition,different and similar thickness.In addition,based on the above experiments,visual colorimetric experiments and fluorescence imaging experiments were carried out by using different fluorescent dyes and dyes.The above experimental results show that the proposed method is better reproducible,reliable and the coating is stable,firm and uniform as well as relatively smooth surface and controllable thickness.It also exhibited great potential application prospects and value in sensors and sample pretreatment.To investigate the application of the coating preparation method in the preparation of molecularly imprinted polymer coatings,a molecularly imprinted polymer coating of 2,4-dichlorophenoxyacetic acid was prepared.And the related instruments were performed on characterization including surface morphology,water contact angle and composition structure.In addition,the batch binding experiments were carried out to investigate the loading solvent,adsorption time,desorption solvent,adsorption performance as well as specific selectivity.Based on the above optimized conditions,the imprinted coating was applied in prepared complex milk sample.The results indicated that this method can be used to prepare imprinted polymer coating which exhibits better extraction ability,high imprinting effect,and recycled and reused.Moreover,the coating can avoid the cross-contamination and loss due to complicated pretreatment procedure,and further expand the preparation method and application of molecularly imprinted polymer coatings.To further investigate research and develop the application of polymer coatings,the environmental pollutants fluoranthene and estrone were used as the analysis object.And the in-situ fluorescence detection and mass spectrometry imaging experiments were carried out combining with the existing analytical detection techniques and methods.The in-situ fluorescence analysis of fluoranthene showed that the coating exhibits good enrichment ability,improves sensitivity and avoids the phenomenon of fluorescence quenching.It also shows that the coating can be used for the in-situ fluorescence analysis of fluoranthene in the practical samples.In addition,the derivatization of estrone with dansyl chloride were successfully explored by quantitative analysis and mass spectrometry imaging via HPLC-MS/MS and air flow assisted ionization mass spectrometry imaging system.The results demonstrated that the coating has good extraction ability for estrone derivatives and its potential application prospect and value in mass spectrometry imaging.