Preparation And Application Of Alkylphenol Multi-templates Molecularly Imprinted Polymer Based On Magantic Graphene Oxide

Alkylphenols,such as bisphenol A?BPA?,octylphenol?4-tert-OP?,and nonylphenol?4-NP?,are widely used in the industrial field to produce plasticizers,flame retardants,antioxidants,emulsifiers and herbicides.Alkylphenols belong to the environmental endocrine disruptors?EDDs?,which have potential carcinogenic risks to human health.Therefore,to analyze and detect alkylphenols in the environment is essential.Since the low content of alkylphenols and other complicated matrix components with large interference in the environmental samples,to separate and enrich the samples before the detection is of great importance.Solid-phase extraction?SPE?is a type of sample pretreatment technology frequently used by researchers,one of the core issues to be solved is the choice of adsorbent.Conventional adsorbents,such as C18 and activated carbon,have the disadvangages of low adsorption quanities and no specification abilities.In our study,the multi-templates molecularly imprinted polymer?MIP?,with bisphenol A?BPA?,4-tert-octylphenol?4-tert-OP?and 4-nonylphenol?4-NP?as the templates,was prepared.And further we researched its adsorption ability.The method,which was called SPE-DLLME-HPLC,was established.On this basis,we explored its analytical performance,and then applied it to detect alkylphenols in actual environmental water.The study contents are consist of the several parts:1.With magnetic graphene oxide-mesoporous silicon composite grafted with double bond?VTTS-MGO@mSiO₂?as carrier,bisphenol A,4-tert-octylphenol and 4-nonylphenol as template molecules,4-vinylbenzoic acid as the functional monomer,we synthesized the magnetic molecularly imprinted materials,which have high recognizability for the three target compounds.The related factors were optimized by orthogonal optimization experiments:when the amount of bisphenol A,4-tert-octylphenol and 4-nonylphenol was0.175 mmol?1:1:1,molar ratio?,the amount of VTTS-MGO@mSiO₂ is 300 mg,the amount of 4-vinylbenzoic acid and ethylene glycol dimethacrylate is 1.05,2.63 mmol,and the amount of 2,2'-azobisisobutyronitrile is 50mg.The obtained materials were characterized by FTIR?SEM?VSM.2.Adsorption characteristics of the multi-templates MIP for bisphenol A,4-tert-octylphenol and 4-nonylphenol.The results showed that under the condition of 298 K and pH=6,the adsorption capacity of the multi-templates MIP for bispheno A,4-tert-octylphenol and 4-nonylphenol reached the maximum,which were 16.81,35.97 and61.73 mg/g,respectively.Decreasing the temperature is beneficial to the adsorption of the three alkylphenols and all reach equilibrium within 30 min.For the multi-templates MIP,the relative selectivity coefficients of bisphenol A,4-tert-octylphenol and 4-nonylphenol to bisphenol AF?BPAF?are 3.38,4.40,6.66,respectively,and for 4-tert-butylphenol?4-PTBP?were 4.50,5.87,and 8.88,respectively,indicating that the material has good imprinting effect and specific recognition.After 5 cycles of adsorption-desorption-resorption experiments,the adsorption capacity of the multi-templates MIP for bisphenol A,4-tert-octylphenol and 4-nonylphenol decreased by 12%,6%and 8%,respectively.It shows that the material has good recycling performance.The adsorption of bisphenol A,4-tert-octylphenol and 4-nonylphenol accords with the pseudo-second-order kinetic and Langmuir model,telling that the process was a spontaneous physical exothermic adsorption.3.A new method named magnetic SPE-DLLME-HPLC based on the prepared alkylphenol multi-templates MIP was established for the simultaneous determination of BPA,4-tert-OP,4-NP.Optimization of extraction conditions of bisphenol A,4-tert-octylphenol and4-nonylphenol in solid phase extraction and dispersive liquid-liquid microextraction.In SPE,under the solution pH 6,the dosage of MIP and sample volume is 20 mg and 50 mL,the extraction time is 8 min and the eluent is 1 mL acetone.In DLLME,the extractant is 30?L1,1,2,2-tetrachloroethane and the NaCl content is 1%under the solution pH 6.The results showed that the multi-templates MIP was used as the adsorbent for SPE-DLLME.The enrichment factors for bisphenol A,4-tert-octylphenol and 4-nonylphenol were 5013,6530and 6989,respectively.The minimum LOD of the method were 0.013,0.010,0.011?g/L?S/N=3,n=3?,and the LOQ were 0.042,0.034,0.036?g/L?S/N=10,n=3?.The method was applied to the determination of bisphenol A,4-tert-octylphenol and 4-nonylphenol in environmental water.The recoveries of water samples were 81.54¹04.09%,86.95¹04.29%,85.16¹00.93%,relative standard deviation?RSD,n=6?were between 1.72⁷.39%,1.03⁷.57%,2.10⁷.54%.The method has the advantages of high sensitivity,accuracy and separation speed.