| Environmental issue and food safety problems have become increasingly prominent,the analysis and detection of trace biogenic amines(BAs)and antibiotics have become the focus of attention in the society.The selections of sample pretreatment methods and enrichment materials are the focus of trace detection.In this paper,around the construction of new magnetic solid/liquid enrichment materials,four kinds of enrichment materials were designed and prepared by means of structure modification,morphology control and element doping,including two kinds of visual magnetic ionic liquids and two kinds of magnetic carbon-based solid adsorption materials.The four materials were applied to the sample pretreatment technology,and the dispersion liquid-liquid microextraction(DLLME)and dispersion magnetic solid phase extraction(d-MSPE)methods were established.The adsorption kinetics,thermodynamics and adsorption capacity of the materials were studied.Trace biogenic amines(BAs),sulfonamides(SAs)and quinolones(FQs)in a variety of real samples were separated and preenriched with high efficiency,combined with high performance liquid chromatography(HPLC)for highly sensitive detection,and the adsorption mechanism was also systematically revealed.1.This MIL trihexyltetradecylphosphonium tetrachlorocobalt(II)[P+6,6,6,14]2[Co Cl42-]was designed and synthesized by one-step room temperature stirring method.[Co Cl42-]MIL is non-hydrolyzed in water medium,has low UV absorption rate,allows HPLC-UV direct analysis,and has obvious color which is convenient for visual separation and recovery.A simple,rapid and sensitive method based on in situ derivatization combined with magnetic ionic liquid(MIL)-dispersive liquid-liquid microextraction(DLLME)was developed for the determination of six biogenic amines(BAs)(tryptamine,phenylethylamine,histamine,tyramine,spermidine and spermine).The method successfully combines in situ derivatization and extraction,no organic solvent and magnetic technology.Experimental parameters such as MIL mass,volume of derivative agent,type and volume of dispersant,derivation and extraction time,p H value of sample solution were investigated to determine the best extraction conditions.The extraction mechanism between[P+6,6,6,14]2[Co Cl42-]and BAs was investigated,which was mainly due to strong hydrophobic interaction.The proposed method was successfully applied for the analysis of wine and fish samples,and the recoveries of analytes achieved were in the range of 93.2-103.1%and 94.5-102.3%,respectively.The limits of detection(LODs)/limits of quantitation(LOQs)for wine and fish samples were in the range of 1.3-3.9/4.1-9.9?g L-1 and 1.2-3.8/3.9-9.6?g kg-1,respectively.Additionally,good reproducibility with relative standard deviations lower than 4.9%(n=5)was obtained for the analysis of wine and fish samples.The in situ DNS-Cl derivatization and MIL-DLLME method was an efficient,rapid,environmental friendly microextraction approach for the determination of BAs in foodstuffs.2.A multifunctional visual observation of magnetic ionic liquid(MIL)benzyltrioctylammonium thiocyanatecobalt(II)[N+8,8,8,B]2[Co(SCN)42-]with the long-chain alkyl and benzyl group structures was designed and synthesized as microextraction phase.Designed new structural MIL displays good hydrophobicity,high extraction capacity for both aromatic and aliphatic compounds,and has obvious color markers(blue color)which is easy visual separation from aqueous solution through a magnet.Microwave-assisted derivatization coupled with MIL-dispersive liquid-liquid microextraction(DLLME)was established for the determination of six BAs(tryptamine,phenylethylamine,histamine,tyramine,spermidine and spermine).Through univariate and multivariate optimization experiments(Box-Behnken design),the MIL mass,microwave power,microwave time and other experimental parameters were investigated.The sample pretreatment operations of simultaneous derivation and extraction of aromatic biogenic amines(tryptamine,phenylethylamine,histamine and tyramine)and aliphatic biogenic amines(spermidine and spermidine)were completed in 105 s.The adsorption mechanism between[N+8,8,8,B]2[Co(SCN)42-]and BAs has been investigated,which is characterized by?-?interaction and hydrophobic interaction.The method was successfully applied for the analysis of beer and milk samples,and the recoveries of analytes were 93.0-110.3%and 91.2-111.6%,respectively.The limits of detection(LODs)were 0.51-1.49?g L-1 for six BAs.The established method improves the sensitivity and reduces the enrichment time,and the results are satisfactory.3.By template-free and self-doping approach,N enriched magnetic porous carbon spheres(Fe@N-PCS)was designed and synthesized via direct carbonization of melamine-glyoxal polymer containing magnetic element.Interconnected spherical morphology of Fe@N-PCS contains abundant porosities.The rich specific surface area and a large number of mesopores provide an optimized mass transfer pathway and expose a large number of adsorption sites,enhancing the enrichment effect.In the present work,microwave-assisted derivatization coupled with Fe@N-PCS-dispersive magnetic solid phase extraction(d-MSPE)was established for the determination of six BAs(tryptamine,phenylethylamine,histamine,tyramine,spermidine and spermine)in different food samples via HPLC.In order to determine the optimal extraction conditions,by univariate and multivariate methods(Box-Behnken),inspected the derivative and extraction method,the types of adsorbent,adsorbent dosage,microwave power and microwave time.The microwave-assisted derivative and enrichment process only need135 s.The adsorption mechanism between Fe@N-PCS and BAs was investigated,which was characterized by?-?interaction,H bond interaction and hydrophobic interaction.The method was successfully applied for the analysis of orange juice and beer samples with a high enrichment factor(37<EF<39),and the recoveries of analytes were90.6-108.2%and 91.9-106.9%,respectively.The limits of detection(LODs)were0.55-0.68?g L-1 for six BAs.The proposed method further improves the sensitivity and enhances the material cycling performance,and the results are satisfactory.4.A flexible,large-area 3D N-doped magnetic graphene-like carbon(Fe/N@C)was successfully synthesized using cotton as template via freeze drying and one step pyrolysis process.Benefitting from the 3D porous N-doped graphene structure,Fe/N@C can highly enrich pollutants by?-?and H-bond interaction.Fe/N@C coupled with dispersive magnetic solid phase extraction(d-MSPE)was established for the simultaneous determination of five sulfonamides(SAs)and quinolones(FQs)antibiotics(SAs:sulfadiazine and sulfamethoxazole;FQs:levofloxacin,norfloxacin and enrofloxacin),and the removal ability and the separation enrichment ability(trace level)were investigated.Through adsorption kinetics and thermodynamics studies,Fe/N@C shows a high total saturated adsorption capacity and rapid adsorption rate for SAs and FQs antibiotics.The adsorption was in accordance with quasi-second-order kinetics and langmuir model,and the rate was mainly controlled by intra-particle diffusion.The adsorption capacity is 102.2 mg g-1.The adsorption and elution conditions of d-MSPE based on Fe/N@C were optimized.The adsorption mechanism between Fe/N@C and BAs was investigated,which was characterized by?-?interaction,H bond interaction and hydrophobic interaction.The method was successfully applied for the analysis of river and milk samples,and the recoveries of analytes were 91.2-99.9%and 92.2-96.4%,respectively.The limits of detection(LODs)were 0.043-0.067?g L-1 for five antibiotics.The established method has the characteristics of resource saving and environment friendly,with high removal ability and low LODs,and the results are satisfactory.In this paper,a method of microwave simultaneous derivatization and extraction was established.With the microwave response ability of magnetic ionic liquid and carbon-based solid materials,the pretreatment time was shortened and the enrichment operation was simplified.Four kinds of materials were designed for the separation and enrichment of pollutants,and the preparation method was simple,the raw materials were economical and easy to obtain.The performance of the four materials in the separation and enrichment of pollutants was gradually improved.BAs was enriched with three materials of[P+6,6,6,14]2[Co Cl42-],[N+8,8,8,B]2[Co(SCN)42-]and Fe@N-PCS,the time of derivation and extraction is radually shortened,LOD was reduced,recycle performances was enhanced,and the recovery is satisfactory. |
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