Enrichment And Determination Of Typical Environmental Pollutants By Magnetic Solid Phase Extraction With Magnetic Polyamidoamine Dendrimers As Adsorbents

Water pollution is a more prominent environmental problem.There are many varieties of organic pollutants in waters,which pose extreme harm to human health and ecological environment.Therefore,it is essential to develop simple,efficient,rapid and sensitive analytical methods for the determination of organic pollutants.Magnetic solid phase extraction(MSPE)has attracted extensive attention due to its advantages of simplicity,easy separation,low organic solvent consumption,etc.In MSPE procedure,magnetic nanoparticles are used as adsorbents,and nano-ferroferric oxide(Fe3O4)is more-often used magnetic core material.However,the unmodified magnetic nano-Fe3O4 is easy to agglomerate and there are few surface groups,which limits the application scope.Therefore,it is an important and valuable way to modify the surface of nano-Fe3O4 with functional materials.In this paper,the polyamidoamine dendrimers were used to functionally modify the surface of nano-Fe3O4,and as-synthesized magnetic nano-composites were investigated as adsorbents for preconcentration and determination of phthalate esters,phenols,Sudan red dyes and organochlorine pesticides pollutants from environmental water samples in combination with HPLC.The main contents were as follows:In the first part,the polyamidoamine dendrimers were used to modify the surface of nano-Fe3O4 by successive iterative Michael addition reaction and amidation reaction under ultrasocination and transmission electron microscopy,X-ray energy spectrum,fourier transform infrared spectroscopy,X-ray diffraction,elemental analysis and thermogravimetric analysis were used to characterize the morphology,composition,crystal structure and weightlessness characteristics of the as-synthesized composites.In the second part,a new method for simultaneous enrichment and detection of dibenzyl phthalate(DPhP),di-n-pentyl phthalate(DnPP)and dicyclohexyl phthalate(DCHP)from environmental water samples has been developed.Under the optimal experimental conditions,the linear ranges of DPhP,DnPP and DCHP were in the range of 0.1-600 ?g/L,1-600 ?g/L and 0.5-600 ?g/L,respectively.And the limits of detection(LODs)were in the range of 0.025-0.16 ?g/L.The precisions were all below 4.4%.The method was used to analyze the environmental water samples,and satisfied spiked recoveries in the range of 93.5%-101.8%were achieved.In the third part,a novel method for preconcentration and determination of tetrabromobisphenol A(TBBPA)and 4-nonylphenol(4-NP)from environmental water samples has been proposed.Under the optimal experimental conditions,the linear ranges of them were in the range of 0.1-500 ?g/L,and the LODs of TBBPA and 4-NP were 0.017 ?g/L and 0.011 ?g/L,respectively.The precisions of TBBPA and 4-NP were 1.2%and 2.5%,respectively.The method was validated with real water samples,and the spiked recoveries were in the range of 93.2%-101.1%.In the fourth part,a new method for enrichment and detection of Sudan red dyes from environmental water samples has been established.Under the optimal experimental conditions,the linear ranges of target analytes were in the range of 0.02-300 ?g/L,and the LODs were ranging from 0.0018 ?g/L to 0.055 ?g/L.The precisions were less than 3%.The method was validated with environmental water samples,and satisfied spiked recoveries in the range of 92.5%-102.2%were obtained.In the fifth part,a novel method for determination of four organochlorine insecticides(p,p'-DDT,o,p'-DDT,p,p'-DDE and p,p'-DDD)from environmental water samples has been developed.Under the optimal experimental conditions,the linear ranges of targets were in the range of 0.1-500 ?g/L,and the LODs were in the range of 0.012-0.029 ?g/L.The pecisions were less than 4.4%.The method was used to analyze the real water samples,and the spiked recoveries were in the range of 91.8%-103.5%.