The Research On Magnetic Solid Phase Extraction Of Proteins By Ionic Liquid/Deep Eutectic Solvent-coated Magnetic Nanoparticles

Magnetic Solid Phase Extraction(MSPE)is a kind of novel solid phase extraction technology with magnetic materials as adsorbent,which has the characteristics of rapid separation and easy operation.The key of this technology is to design and synthesize functional magnetic adsorbent.Ionic liquid(IL)and deep eutectic solvent(DES)have the advantages of structural design and functionalization.Immobilized on magnetic particles as adsorbents for magnetic solid phase extraction,not only can realize selective extraction that is difficult for organic solvent,but also be friendly to atmospheric environment and reduce the loss of operation process.Ionic liquids and deep eutectic solvents based magnetic adsorbents are used in magnetic solid phase extraction to specifically adsorb target analytes by hydrogen bonding,?-? and electrostatic forces.Thus,magnetic solid phase extraction technology will be more widely applied when combined with ionic liquid or deep eutectic solvent.In this work,two types of green solvents,IL and DES,were synthesised.In combination with magnetic solid phase extraction,a method for protein extraction is established.The main contents of the present study are as follows:(1)Magnetic solid-phase extraction of protein by ionic liquid-coated Fe@grapheneoxideAmino functional dicationic ionic liquid(AFDCIL)was prepared and then coated on the surface of magnetic grapheneoxide(Fe@GO)as a new magnetic adsorbent(Fe@GO@AFDCIL)for the magnetic solid-phase extraction of protein.The Fe@GO@AFDCIL composite was characterized by vibrating sample magnetometer(VSM),X-ray diffraction(XRD),fourier transform infrared spectrometry(FT-IR),thermal gravimetrican alysis(TGA),field emission scanning electron microscopy(FESEM)and Zeta-potential nanoparticles.The bovine hemoglobin(BHb)was used as the analyte,and the extraction performance of Fe@GO@AFDCIL was investigated in the MSPE procedure.The concentrations of BHb in samples were determined by a UV-vis spectrophotometer.A comparative investigation of Fe@GO@AFDCIL composite and traditional IL-coated Fe@GO composites exhibited the benefits of Fe@GO@AFDCIL.Single factor experiments were carried out to study the influence of pH value,solution temperature,concentration of BHb,extraction time,the amount of Fe@GO@AFDCIL,and solution ionic strength.Under the optimized condition,the extraction capacity could reach 174.54 mg/g.The adsorbed BHb could be eluted from the Fe@GO@AFDCIL by 4%sodium dodecyl sulfate(SDS)solution,and elution efficiency could reach 89.54%.Detected by circular dichroism spectra(CD spectra),proving that the secondary structures of BHb eluted from the solid extractants maintained unchange.The Fe@GO@AFDCIL exhibited favorable stability which could be reused at least 15 times.Under the optimized condition,the real samples were investigated,which demonstrated that the Fe@GO@AFDCIL was able to be applied in extracting BHb from the porcine blood and bovine blood samples.The precision,repeatability and stability of the proposed method were favorable.The proposed method provided new opportunities in extracting proteins.(2)A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu,Zn-superoxide dismutaseA novel magnetic adsorbent,benzyl groups functionalized imidazolium-based polymeric ionic liquid(PIL)-coated magnetic multiwalled carbon nanotubes(MWCNTs)(m-MWCNTs@PIL),has been successfully synthesized and applied for the extraction of Cu,Zn-superoxide dismutase(Cu,Zn-SOD).The m-MWCNTs@PIL composite was characterized by XRD,FTIR,TGA,FESEM,VSM and Zeta-potential nanoparticles.In this method,the m-MWCNTs@PIL could interact with Cu,Zn-SOD through hydrogen bonding,?-? and electrostatic interactions.The extraction performance of the m-MWCNTs@PIL in the MSPE procedure was investigated,coupled with the determination by UV-vis spectrophotometer.Single factor experiments were carried out to study the influence of extraction time,solution temperature,the amount of m-MWCNTs@PIL,pH value,concentration of Cu,Zn-SOD and solution ionic strength.Under the optimized condition,the extraction capacity could reach 85.28 mg/g.The adsorbed Cu,Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 mol/L NaCl solution,and elution efficiency could reach 89.54%.Besides,the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu,Zn-SOD from the porcine blood samples.Under the optimal conditions,the precision,repeatability and stability of the proposed method were favorable.On the basis of these results,the developed method has great potential in the extraction of Cu,Zn-SOD or other analytes from biological samples.(3)A novel ternary deep eutectic solvent-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu,Zn-superoxide dismutaseA novel ternary eutectic solvent(TDES)with tetramethylammonium chloride as hydrogen bond acceptor was prepared.TDES coated magnetic multiwalled carbon nanotubes(m-MWCNTs@TDES)has been successfully synthesized and applied for the extraction of Cu,Zn-SOD.The m-MWCNTs@TDES composite was characterized by XRD,FTIR,TGA,transmission electron microscopy(TEM),VSM and Zeta-potential nanoparticles.The extraction performance of the m-MWCNTs@TDES in the MSPE procedure was investigated,coupled with the determination by UV-vis spectrophotometer.Single factor experiments were carried out to study the influence of extraction time,solution temperature,the amount of m-MWCNTs@TDES,pH value and concentration of Cu,Zn-SOD.Under the optimized condition,the extraction capacity could reach 60.75 mg/g.The adsorbed Cu,Zn-SOD remained high specific activity after being eluted from m-MWCNTs@TDES by 1 mol/L NaCl solution and elution efficiency could reach 74.26%.Besides,the m-MWCNTs@TDES could be easily recycled and successfully employed in the extraction of Cu,Zn-SOD from the porcine blood samples.Under the optimal conditions,the precision,repeatability and stability of the proposed method were favorable.On the basis of these results,the developed method has great potential in the extraction of Cu,Zn-SOD or other analytes from biological samples.