| Based on molecular design, in this work,with chloromethylated polystyrene(CMPSF) membrane was as base membrane, two different kind of molecularlyimprinted membranes with graft-type for the pesticide was prepared by using two newimprinting technology of―synchronously graft-polymerizing and imprinting‖and―synchronously graft-polymerizing then imprinting‖. The pesticide-potentiometricsensor constituted with the membrane as sensitive membrane not only has the advantageof the simple establishment process, but also its detection is sensitive and accurate.Obviously, the results of this research has obvious scientific significance in thepreparation of high-performance molecular imprinted membrane and importantapplication value in environmental monitoring and protection.Chloromethylated polysulfone (CMPSF) was first prepared by usingchloromethylation reagent, and then the CMPSF membrane was casted. Subsequently,CMPSF membrane was aminated with ethanediamine (EDA) as reagent, and aminogroups were introduced onto the surface of PSF membrane, obtained the aminationmembrane AMPSF. On this basis, a surface-initiating system was constituted by theamino group-NH2on the surface of AMPSF membrane and peroxysulphate in theaqueous solution, and it initiated sodium p-styrenesulfonate (SSS) to begraft-polymerized, obtaining the grafted membrane PSF-g-PSSS. The effects of mainfactors on the graft-polymerization were investigated in depth, and the reactionconditions were optimized. The grafted membrane PSF-g-PSSS was characterized byinfrared spectroscopy (FTIR) and optical microscope (OM) as well as weight method.Finally, the adsorption characters of the grafted membrane PSF-g-PSSS for two nitrogen-containing heterocyclic ring pesticides, pirimicarb and atrazine, wereexamined. The experimental results show that by using surface-initiating system ofamino group/peroxysulphate, the graft-polymerization of SSS on the surface of PSFmembrane can be successfully realized, and the grafting degree of PSSS increases withthe content of amino group on the basement membrane AMPSF. The suitabletemperature for the graft-polymerization of SSS is70℃, and the appropriateconcentration of the initiator peroxysulphate in the solution is0.3%of the monomermass. By right of strong electrostatic interaction between host and guest, the graftedmembrane can produce strong adsorption action for pirimicarb and atrazine molecules.The result of this research feasibility the foundation of prepare molecularly imprintedmembranes by using chloromethylated polystyrene (CMPSF) membrane as the basemembrane.Secondly, a kind of molecularly imprinted membranes with graft-type for thepesticide pirimicarb was prepared by using a new imprinting technology of―synchronously graft-polymerizing and imprinting‖. In this process, chloromethylatedpolystyrene (CMPSF) membrane was as base membrane, the anionic monomer sodiump-styrenesulfonate (SSS) was used as functional monomer andN,N’-methylenebisacrylamide (MBA) was used as crosslinker. By the initiating of asurface-initiating system of-NH2/S2O82-, the graft-polymerization/crosslinking of SSSand MBA that were combined around the template molecule of pirimicarb was realized,resulting in the pirimicarb-imprinted membrane. The imprinted membrane wascharacterized by infrared spectroscopy (FITR) and optical microscope (OM). On thisbasis, the molecular recognition ability and mechanism of the imprinted membrane wereexamined and investigated in depth. The experimental results show that the preparedimprinted membrane possesses the specific recognition selectivity and excellent bindingaffinity for the template pirimicarb molecule, and the binding capacity gets up to92μg/cm2. Relative to another pesticide, atrazine, whose structure is similar to that ofpirimicarb to a certain degree, the coefficient of selectivity of the imprinted membrane reaches4.54.Then, the potentiometric sensor was constituted with pirimicarb-imprintedmembrane as sensitive membrane not only has the advantage of the simple establishmentprocess, but also its detection is sensitive and accurate. In aqueous medium of pH=4, thissensor offers a linear response to pirimicarb over the range of1×10-6～1×10-3mol/L (alinear correlation coefficient of0.9999) with a lower detection limit of2.5×10-8mol/L,and it has a faster response time of fewer than10s.Atrazine imprinted membrane was prepared by using imprinting technology of―synchronously graft-polymerizing then imprinting‖in this study. In this process, themethacrylic acid (MAA) was used as functional monomer, By the initiating of asurface-initiating system of-NH2/S2O82-, and it initiated MAA to be graft-polymerized,obtaining the grafted membrane PSF-g-PMAA, and the adsorption characters of thegrafted membrane for two atrazine was examined. The experimental results show thatthe grafted membrane can produce strong adsorption action for atrazine by right ofstrong electrostatic interaction between host and guest. And then, The another molecularimprinted membrane was prepared with atrazine as template molecule and with ethyleneglycol diglycidyl ether (EGDE) as crosslinker. the prepared imprinted membranepossesses the specific recognition selectivity for the template atrazine molecule. Finally,pirimicarb-potentiometric sensor was constituted by using the pirimicarb-imprintedmembrane as sensitive membrane, and the detecting performance of this potentiometricsensor was evaluated. the potentiometric sensor constituted with atrazine-imprintedmembrane as sensitive membrane not only has the advantage of the simple establishmentprocess, but also its detection is sensitive and accurate. this sensor offers a linearresponse to pirimicarb over the range of1×10-7～1×10-4mol/L with a lower detectionlimit of4.7×10-8mol/L, and it has a faster response time of fewer than10s. |
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