A Study On The Synthesis Of Magnetic SiO₂Microspheres And The Separation Of Angioensini Converting Enzyme Inhibitory Peptides

The synthesized Fe3O4@SiO2microspheres had the characteristics of superparamagnetism. It also had good biocompatibility and chemical stability, large specific surface area, and it was easy to be modificated by use silane coupling agent. These characteristics made Fe3O4@SiO2microspheres have broad application prospects. And Fe3O4@SiO2microspheres had important biomedical applications on purification of DNA, protein and peptides. In this paper, Fe3O4@SiO2-Cu was synthesized by optimizing a series of process conditions as the affinity medium. HLPLP which had antihypertensive activity was used as model molecules to study the law of affinity adsorption on Fe3O4@SiO2-Cu2+. It provided a theoretical basis for studying the purification of ACE on IMAN.Fe3O4was prepared by chemical coprecipitation. Influence factors on the average particle size of Fe3O4was optimized:4.0g FeCl2-4H2O and10.8g FeCl3-6H2O was raw materials, reaction temperature was333K, stirring speed was700rpm, volume of NH4OH was24mL, current speed of NH4OH was2mL-min-1. The average particle size of Fe3O4was66nm, and the magnetization of Fe3O4was103.358emu·g-1. microspheres was prepared by reversed phase emulsion. Influence factors on the average particle size of Fe3O4@SiO2microspheres was optimized:0.1g Fe3O4was raw materials, volume of TEOS was1mL, volume of Trition X-100was0.2mL, ratio between C2H5OH and H2O was1, time was2h. The average particle size of Fe3O4@SiO2was284nm, and the magnetization of Fe3O4@SiO2microspheres was31.349emu·g-1.Epoxy group was introduced by using silane coupling agent GLYMO. Influence factors on the density of epoxy group was optimized:0.1g Fe3O4@SiO2microspheres was raw materials, time was20h, volume of GLYMO was2.5mL, volume of C2H5OH was40mL. The density of epoxy group was75μmol·g-1. Cu2+was introduced by using IDA. Influence factors on the density of Cu2+was optimized:0.1g Fe3O4@SiO2microspheres was raw materials, time was6h, stirring speed was150rpm, reaction temperature was363K. The density of Cu2+was28.8μmol·g-1.HLPLP which had antihypertensive activity was used as model molecules to studiy the law of affinity adsorption on Fe3O4@SiO2-Cu. Influence factors on the adsorption of HLPLP was optimized:concentration of HLPLP was0.35mg·mL-1, pH was7.5, time was60min. The saturated adsorption of HLPLP was32.2mg·g-1. Fe3O4@SiO2microspheres’nonspecific adsorption on HLPLP was small. Fe3O4@SiO2-Cu2+can be used at least3times and kept a high adsorption capacity. The adsorption of HLPLP on Fe3O4@SiO2-Cu accorded with Freundlich model; The adsorption kinetics of HLPLP on Fe3O4@SiO2-Cu2+ accorded with Pseudo second-order kinetic adsorption kinetics.