| An acephate mesoporous molecularly imprinted polymer(MIP) was prepared by sol-gel technique using acephate as template molecule,3 aminopropyl propyl triethoxysilane(APTES) as functional monomer,surfactant dodecylamine(DDA) as mesoporous template and tetraethoxysilane as coupling agent.And it was characterized.Results of Scatchard analysis showed that there existed two kinds of binding sites.The values of apparent maximum absorption capacity were calculated as follows:Qmax1=4703 mg/g and Qmax2=9031 mg/g,and the dissociation constants:kd1=5714 mg/L and kd2=18868 mg/L.The adsorptive dynamics results showed that the adsorption of the polymer toward acephate accorded with quasi secondary dynamics model.The results of adsorption thermodynamics showed that the adsorption process was exothermic.The prepared polymer was used for matrix solid phase dispersion(MSPD) extraction of acephate in grains.The optimum experimental conditions were as follows:the ratio of polymer to sample:1∶1,grinding time:8 minutes,the washing solvent:ethanol-water(2∶1,by volume),the eluent:acetonitrile-acetic acid(19∶1,by volume).The final eluent was detected by high performance liquid chromatography,and the calibration curve of acephate was linear in the range of 003-03 μg/g with a detection limit of 0015 μg/g.Recoveries for acephate were between 925%and 971%with relative standard deviations(RSD) of 29%-37%.With the advantages of high selectivity of mesoporous molecularly imprinting technique and the rapid separation of matrix solid phase dispersion extraction,this method provides a new idea for the residue analysis of acephate. |