Monocrotophos Molecularly Imprinted Microspheres Prepared by Precipitation Polymerization in Acetonitrile

Molecularly imprinted microspheres (MIP) for monocrotophos have been prepared by precipitation polymerization in acetonitrile (ACN) 60℃,24 h,using methacrylic acid (MAA),ethylene glycol dimethacrylate (EGDMA) and 2, 2-azobisiobutyronitrile (AIBN) as functional monomer,cross-linker and initiator,respectively.The recognition mechanism was elucidated by UV-vis spectra and computer modeling.Equilibrium binding experiment was employed to investigate the rebinding properties,Scatchard analysis showed that specific binding sites formed in the imprinted microspheres,and there were two kinds of binding sites,one was high binding sites,the other was low binding sites.This microspheres can be useful affinity absorbent used for organophosphorus pesticides separation and purification in food and environmental analysis.

Preparation of Thermosensitive Hollow Imprinted Microspheres via Combining Distillation Precipitation Polymerization and Thiol-ene Click Chemistry

Hollow molecular imprinted polymer microspheres were prepared by distillation precipitation polymerization with(S)-(+)-ibuprofen(S-IBF)as template molecule and acrylamide(AM)as functional monomer.Using the silicon dioxide(SiO_(2),180 nm)modified by 3-(trimethoxysilyl)propyl methacrylate(MPS)as the template micro-spheres,the molecular imprinted shells were coated on successfully(SiO_(2)@MIPs).The thermosensitive SiO_(2)@MIPs-PNIPAM core-shell microspheres were subsequently prepared by grafting the PNIPAM chains(M_(n)=1.21×10^(4)g/mol,polydispersity index=1.30),which were prepared by reversible addition-fragmentation chain transfer(RAFT)polymerization,on the surface of SiO_(2)@MIPs microspheres via the thiol-ene click chemistry.The grafting density of PNIPAM brushes on the SiO_(2)@MIPs microspheres was about 0.18 chains/nm^(2).After HF etching,the hollow imprinted microspheres were finally obtained.For thermosensitivity analysis,the phase transition temperatures of multifunctional nanoparticles were measured by DSL at 25℃and 45℃respectively,and the sizes of the microspheres changed by about 35 nm.The modified microspheres presented excellent controlled release property to S-IBF,moreover about half amount of the adsorptions passed into acetonitrile-water solution through the specific holes of imprinted shell at 25℃under vibration.