Fe₃O₄ Magnetic Nanoparticles-based For Studying Ambient Ionization Mass Spectrometry

Recently, nanoparticles have become one of the important advanced research field, magnetic materials have been widely used in environmental protection biological medicine, food security and other fields for its unique magnetic property. Fe3O4 magnetic nanoparticles, with its simple synthesis process, easy to separate and large surface area, make it easy to form coordination bonds with compounds with special structure in water or methanol and result in a good selective adsorption properties. Fe3O4 magnetic nanoparticles have offered a new way of separation, purification and enrichment to complex compounds.Paper spray mass spectrometry(MS) is a new branch of ambient ionization mass spectrometry(MS), paper spray ionization has good development prospects and wide application fields. Direct spray paper-MS, easy to operate and without sample pre-processing, can performce real-time analysis on the sample surface, however, with many interference factors in the open environment during the analysis, the detection sensitivity is not good. In this paper, we utilize the selective adsorption properties of Fe3O4 combine with paper spray mass spectrometry, have effectively improved detection sensitivity. Provide a fast and precise analysis method. More details are as follows:1. The Fe3O4 magnetic nanoparticles were synthesized by coprecipitation in this article.Several factors to the purity and particle size of Fe3O4 magnetic nanoparticles such as molar ratio of ferrous to ferric ions, total ferric concentration and Ph have been researched. The structure, morphology and magnetism performance of nanoparticles has been characterized by transmission electron microscope(TEM),fourier transform infrared spectrometer(FTIR) and dynamic laser light scattering apparatus(DLS).The optimal reaction conditions are as follows, molar ratio of ferrous to ferric ions at 1:2, pH value at 10.0. Under the optimal condition, small sized and monodispersed Fe3O4 nanoparticles could be obtained.2. In order to explore the selective adsorption properties of Fe3O4 magnetic nanoparticles. Fe3O4 magnetic nanoparticles are used as a carrier for adsorption of marijuana sample extract, ginkgo biloba crude purified liquid, angiotensin 2 and angiotensin 2(phosphorylation) adsorption, and then characterized with open paper ionization mass spectrometry. The results show that Fe3O4 magnetic nanoparticles have selective absorption to the compounds with ortho-position phenolic hydroxyl group and carboxylic acids structure.3. Using the absorption properties of Fe3O4 magnetic nanoparticles to the compound with carboxyl group and benzene ring, the adsorbtion and enrichment of citrinin in monscuspurpureus have been researched. The results show that this method have simplified the process of separation and purification of complex sample, have reduced minimum detectable concentration of citrinin with open paper spray mass spectrometry. Then charactrize the entire testing process analysis using paper ionization mass spectrometry. Compared with traditional methods, this method is more simple and efficient.