Preparation,Charaeterization And Application Of Hydrophilic Molecularly Imprinted Microspheres For Difenoconazole

Hydrophilic molecularly imprinted microspheres?HMIMs?for difenoconazole were prepared by precipitation polymerization using 2-hydroxypropyl methacrylate?HPMA?as functional monomer,ethylene glycol dimethacrylate as cross-linker,azobisisobutyronitrile as initiator,and mixture of butanone and n-heptane?6:4,V:V?as solvent.The morphological particle sizes and structures were determined via scanning electron microscopy,laser particle size analyzer,and Fourier transform infrared spectrometry.The average particle size of HMIMs and hydrophilic molecularly non-imprinted microspheres?HNIMs?were 2.72 and 3.28?m,respectively.BET specific surface area analysis showed compared with HNIMs the specific surface area analysis of HMIMs were smaller but the adsorption constant?C?of HMIMs were better than HNIMs.What's more,The solvent could influence the value of specific surface area.Equilibrium adsorption experiments were performed in distilled water to evaluate the adsorption capacity of the obtained microspheres towards difenoconazole.Scatchard model shows the maximum adsorption(Q_max)of HMIMs and HNIMs for difenoconazole are 65.04and 56.97 mg·g^-1.These results indicated that HMIMs had specific and homogeneous adsorption cavities.Langmuir isotherm presents Q_max of HMIMs and HNIMs are 62.89 and53.19 mg·g^-1 and assumes that adsorption of HMIM1 is belong to monolayer adsorption.Binding kinetics analysis showed the adsorption of HMIMs to difenoconazole was well fitted the pseudo-second-order kinetic model with a good linear relation?R²=0.9963?and illustrated that the adsorption process of HMIMs is belong to chemical adsorption.Selectivity analysis presented the order selectivity of HMIMs for difenoconazole and its analogues was difenoconazole>tebuconazole>triadimefon.This result proved HMIM1 possessed highly specific binding sites for difenoconazole while recognition cavities in HNIMs were non-selective.A hydrophilic molecularly imprinted dispersive solid-phase extraction?HMIDSPE?coupled with gas chromatograph?GC?method was developed for recognizing difenoconazole in tap water,underground water,South Lake water and Yitong River samples?Changchun,China?.The recoveries of difenoconazole in four different kinds of spiked water samples ranged between 75.05%and 91.27%with relative standard deviations?RSDs?were between 4.36 and9.26?n=5?.The limit of detection?LOD,S/N=3?was 0.004 mg·kg^-1.This method meets the requirements of difenoconazole residue analysis.