Synthesis and analysis of the properties of sorbents based on magnetic, molecularly printed polymers that selectively adsorb biogenic amines

The subject of my scientific interests are molecularly imprinted polymers (MIPs). The process of creating MIPs known as molecular imprinting consists in the polymerization of functional monomers and a cross-linking agent in the presence of a molecule called a template. The result of the synthesis is a polymer that specifically and selectively captures the standard or its structural analogs. MIPs are chemically and thermally stable and resistant to various physicochemical factors (e.g. high pressure, various types of radiation). Due to their properties, polymers with molecular footprints are used, among others, in analytical methods (juko-sorbents in solid phase extraction, sensors, column fillings), as drug release systems, catalysts in synthesis. In my work I deal with simulations of prepolymerization systems, polymers, the adsorption process and theoretical analysis of interactions determining molecular recognition in MIPs systems. I also conduct experimental work involving the synthesis and research on the properties of MIPs. Despite the favorable properties of traditional MIPs (obtained by block or precipitation polymerization), there are limitations in their use related to the time-consuming separation of the appropriate bed or the pattern remaining in the polymer matrix after the treatment process. One way to overcome these difficulties may be to obtain magnetic molecularly imprinted polymers (MMIPs). Their isolation from the reaction mixture does not require centrifugation and filtration and is easier than with traditional polymers due to the possibility of using an external magnetic field. The external magnetic field simplifies the application of MMIPs when separating compounds and as drug carriers to a target site in the body. This project covers preliminary studies on the preparation and analysis of the properties of MMIPs. As part of the project, I am going to obtain MMIPs intended for the separation of biogenic amines. In the first stage, the synthesis of iron (II) oxide (III) (Fe3O4) will be performed. The next step will be to modify the surface of magnetic particles (magnetic nanoparticles, MNPs). For this purpose, the MNPs will be coated with a SiO2 layer using tetraethoxysiloxane and then functionalized with a suitable silane and optionally a surfactant. In the next stage, the synthesis of appropriate polymers will be performed with the molecular trace of the selected pattern. As a reference, I will use NN-dimethyl-2-phenylethylamine, which is a structural analog of the biogenic amine - 4- (2-dimethylaminoethyl) phenol hordenine. I am going to make four polymers with a molecular footprint using different functional monomers: acrylic acid, methacrylic acid, 4-vinylbenzoic acid and itaconic acid. The final process will be to remove the standard through Soxhlet extraction. The analytical part will include the analysis of the adsorption capacity and affinity of the obtained polymers to hordenine. In the analysis of adsorption properties, I will use the stationary method. I will choose one polymer for further research, showing the best properties (the highest affinity to the analyte and the highest adsorption capacity). I will determine the physicochemical parameters of the selected polymer, such as: adsorption kinetics, size and surface of the grains, chemical composition, magnetic properties, and I will perform a thermogravimetric analysis. I will optimize the adsorption process by examining the influence of pH, temperature and ionic strength of the solution on the adsorption capacity of the analyte on the imprinted polymer. I will examine the selectivity of the polymer in relation to various biogenic compounds (tyramine, synephrine, octopamine, tryptamine, tyrosine) and the ability of the polymer to adsorb hordenine in model and biological samples. Hardenin was selected as the target analyte because, to the best of my knowledge, there are no literature reports on molecularly printed polymers for the selective adsorption of this biogenic amine. At the same time, hordenine affects the functioning of the body: it stimulates the release of gastrin, inhibits monoamine oxidase B, and also inhibits melanogenesis in human melanocytes. Due to the possibility of its consumption in fruits, herbs and dietary supplements, there is a need to monitor its concentration in blood and urine. The most frequently described method of quantifying hordenine in the literature is HPLC-UV, which requires isolation of the compound and elimination of the matrix by solid phase extraction. Unfortunately, commercially available sorbents do not fulfill their role in the extraction of hordenine. Therefore, there is a need to find a selective sorbent that will allow a simple and effective extraction of the analyzed amine from complex samples, while eliminating the influence of the biological matrix on further quantitative determinations. The expected effect of the activities described in the project will be to increase the knowledge of MMIPs, interfering compounds and the process of molecular imprinting of amines. The obtained MMIP will facilitate the quantification of hordenine in biological samples. The obtained results of preliminary studies will help to develop optimal conditions for obtaining and analyzing MMIPs intended for the separation of various analytes and will be helpful in further work on the preparation of drug forms enabling the release of the active substance in a specific place or organ in the organism.