Design and Preparation of Molecularly Imprinted Membrane with Graft-type and Constitution of Potentiometric Sensor of Pesticides and Its Detection Performance

KeyWord:molecularly imprinted membrane  selectivity of molecule recognition  polysulfone  sodium p-styrenesulfonate  pirimicarb  potentiometric sensor

Abstract:

      Based on molecular design,a kind of molecularly imprinted membranes with graft type for the pesticide pirimicarb was firstly prepared by using a new imprinting technology of ¡°synchronously graft-polymerizing and imprinting¡±.In this process,chloromethylated polystyrene(CMPSF) membrane was as base membrane,the anionic monomer sodium p-styrenesulfonate(SSS) was used as functional monomer and N,N¡¯-methylenebisacrylamide(MBA) was as crosslinker.By the initiating of a surface-initiating system of-NH2/S2O2-8,the graft-polymerization/crosslinking of SSS and MBA that were combined around the template molecule of pirimicarb was realized,resulting in the pirimicarb-imprinted membrane.The imprinted membrane was characterized by infrared spectroscopy(FITR) and optical microscope(OM).On this basis,the molecular recognition ability and mechanism of the imprinted membrane were examined and investigated in depth.Finally,pirimicarb-potentiometric sensor was constituted by using the pirimicarb-imprinted membrane as sensitive membrane,and the detecting performance of this potentiometric sensor was evaluated.The results show that the prepared imprinted membrane possesses the specific recognition selectivity and excellent binding affinity for the template pirimicarb molecule,and the binding capacity gets up to 92 ¦Ìg/cm2.Relative to another pesticide,atrazine,whose structure is similar to that of pirimicarb in a certain degree,the coefficient of selectivity of the imprinted membrane could reach to 4.537.In pH 4.0 aqueous medium,this sensor offers a linear response to pirimicarb over the range of 1.0¡Á10-6-1.0¡Á10-3 mol/L(r=0.999 9) with a lower detection limit of 2.5¡Á10-8 mol/L.The potentiometric sensor constituted with pirimicarb-imprinted membrane as sensitive membrane shows the advantage of simple establishment process, sensitive detection and faster response(t<10 s).