Preparation And Performance Study Of Polystyrene Microspheres

Polystyrene(PS)has been extensively used for chromatographic separations,adsorption of proteins and treatment of wastewater due to its characteristics such as homogeneous size and invariant surface.There is little available quantitative experimental data on the correlation between adsorption and desorption behaviors of various analytes on PS substrates from different sources,which restricts greatly the understanding and the interpretation of different molecular interactions on PS supports.In view of this fact,this paper adopted the dispersion polymerization method to prepare a series of polystyrene microspheres by changing the experimental parameters.Using the vacuum filtration method to coating the PS on the commodity filter paper.The adsorption and desorption behaviors of several pharmaceutical drugs on the PS surfaces were using paper spray mass spectrometry and at the same time,the PS was successfully used as coating materials for paper spray in high-sensitivity analysis of various therapeutic drugs in complex biological matrices.In this research,the main works had been performed as follows:(1)Preparation of PS: The polystyrene microspheres have been synthesized by dispersion polymerization with poly(vinyl pyrrolidone)as dispersant,benzoyl peroxide as initiator,the mixture of absolute ethyl alcohol and deionized water as dispersion medium,styrene as the monomer.The results indicated that the particle size of polystyrene microspheres with uniform size and good monodispersity could be well-controlled in the range of 1 to 15 ?m,and the polymerization degree could be well-controlled in the range of 5,723-91,511.(2)The research of the adsorption and desorption behaviors on polystyrene microspheres:Using the vacuum filtration method to coating the PS on the commodity filter paper and the adsorption and desorption behaviors of several pharmaceutical drugs on the PS surfaces were investigated using paper spray mass spectrometry.The adsorption and desorption performance of drug compounds have been changed with the change of the polystyrene preparation conditions.It was generally accepted that a weaker adsorption interaction would lead to a more favorable desorption behavior,by contrast,one instance of abnormal adsorption and desorption behaviors were presented as follow: the stronger the adsorption interactions between polystyrene and pharmaceutical drugs,the more favorable desorption of those drugs from polystyrene.The same results were observed for the commodity polystyrene.In contrast,when different metal oxides and metal-organic frameworks were employed,the opposite result was obtained.(3)Exploration of the mechanism of polystyrene adsorption-desorption: the FT-IR method was used to study the surface properties of as-prepared PS particles,the results illustrated that the adsorption interaction of PS particles was closely related to the hydrogen bond interaction between the studied drug and PS,and a weaker IR absorption band would result in a stronger adsorption interaction at PS surfaces.Through the change in color of methylene blue on the coated paper to probe the desorption mechanism of methylene blue on PS-coated papers,the result demonstrated that the color of methylene blue on both sides changed a lot before and after applying solvent and voltage that was reasonably due to the analytes of interest which could be extracted in a facile manner out by solvent from the PScoated paper substrate and then moved to the tip of paper for spray along with the applied solvent.The surface energy was used to study the distribution coefficient of analytes between the polystyrene and solvent.As the solvent was applied to the PS-coated paper,it could not be able to wet the PS surface well because the solvents(acetonitrile and methanol)currently having a lower surface energy than that of PS particles.Because of the limited wetting,it might limit the re-distribution of analytes back into the PS surface after dissolving into the applied solvent.The higher the surface energy of PS particles,the more limited the wetting behavior.(4)The PS was also used as coating materials for paper spray in analysis of therapeutic drugs in complex biological matrices: The sensitivity of mass spectrometry was greatly improved by the use of polystyrene as a paper substrate for modification of paper spray ionization mass spectrometry.In contrast to the uncoated filter paper,an improvement of 10-546-fold in sensitivity was achieved using PS coated paper for paper spray,and an estimated lower limit of quantitation(LLOQs)in the range of 0.004-0.084 ng mL-1was obtained in analysis of the therapeutic drugs in various biological matrices such as whole blood,serum and urine.The repeatability and reproducibility were excellently performed by experimental analysis using Paper Spray-Mass Spectrometry.