| Propazine,as a member of triazine herbicides,has been widely used to control broadleaf weeds and annual weeds which grown in the fields of corm,sorghum or other grown.In most kinds of soil,propazine has a poor adsorption and worst in the sand and clay,slightly soluble in water.For monitoring triazine pesticides,the US Food and Drug Administration（USFDA）has formulated maximum residue levels（MRLs）of propazine in maize,0.1-0.25 mg kg-1.To study a new,efficient and environmentally friendly analysis method of propazine residue has become an important duty.In this paper,TiO2 as the carrier was modificated by two-step using APTS and acryloylchloride,synthesized propazine molecularly imprinted polymer（MIP）at the surface at TiO2.The structural characterization and adsorption performance of MIP were tested.The solid phase extraction column with MIP as adsorbent（MISPE）was prepared and used to detect propazine,structural analogues simazine and atrazine in environmental samples.1.Preparation of MIPR Activated TiO2 was modified with 3-aminopropyl triethoxysilane,then acylated with acryloyl chloride.Then modified TiO2 as the carrier,propazine as a template,ethyleneglycol dimethacrylate（EGDMA）as a crosslinker,methacrylic acid（MAA）as a functional monomer,2,2’-Azobis（isobutyronitrile）（AIBN）as an initiator and toluene as solvent,grafted MIP thin was successfully prepared on the surface of carrier.2.Evaluation structural characterization and adsorption of MIPs.Through molecular modeling software simulated the binding sites and ratio between template and functional monomer.Fourier transmission infrared spectrometry（FT-IR）,scanning electron microscope（SEM）,transmission electron microscope（TEM）and X-ray diffraction（XRD）were used to characterize the graft results,appearance of the structure and blotting membrane thickness of intermediates and MIP.To study the MIP adsorption capacity for the template molecule,isothermal adsorption and dynamic adsorption experiments were performed.Compared with the NIP,MIP showed stronger selective adsorption for propazine.When the initial concentration of propazine was 11 mg L-1,the MIP adsorption of propzine was 6.8076 mg g-1,and the adsorption reached 90%of the maximum adsorption capacity in 8 h.When the concentrations of propzine（Pro）and similar compounds simazine（Sim）,atrazine（Atr）and acetanilide（Ace）were all 0.03 mmol L-1,the MIP maximum adsorption capacitance of propzine was 4.15 mg g-1.Meanwhile MIP also showed crosslinked selective adsorption properties of simazine（Sim）and atrazine（Atr）.When the concentration of the competitive compounds about twice to the concentration of the template molecule,MIP still showed a good identify ability to propzine.3.The MISPE columns were prepared using MIPs as adsorbent.A new method of determination of simazine,atrazine and propazine residues was established in water,soil,maize and maize grains.When the adding concentrations of each pesticides in water was 0.05,0.5 and 1.0 mg L"1,in soil,maize and maize grain was 0.04,0.4 and 4 mg kg-1,the average recoveries of Pro,Atr and Sim in water,soil,maize and maize grain was 91.6-103.3%,78.0-99.8%,82.0-99.0%and 86.0%-99.3%,RSD was 0.03-2.04%,0.12-6.42%,0.16-6.79%and 0.09-2.75%.Compared with the Cis-SPE,the highly selective separation and enrichment of Pro,Atr and Sim from the complex environmental media can be achieved by the newly developed molecular imprinting on the surface of nano-TiO2. |
