Preparation,Characterization And Application Of Hydrophilic Molecularly Imprinted Polymers For Azoxystrobin

In this paper,hydrophilic molecularly imprinted polymers（HMIPs）for azoxystrobin were successfully synthesized by precipitation polymerization using azoxystrobin as template molecule,2-hydroxypropyl methacrylate（HPMA）as functional monomer,ethylene glycol dimethacrylate（EGDMA）as cross-linker,azobisisobutyronitrile（AIBN）as initiator,and mixture solution of butanone and n-heptane（7:3,V:V）as solvent.The particle sizes,morphology and structures were determined by scanning electron microscopy（SEM）,laser particle size analyzer,Fourier transform infrared spectrometry（FTIR）and thermogravimetric analysis（TGA）.The results showed that HMIPs had regular shapes,uniform distribution and stable structures.Azoxystrobin was successfully participated in the polymerization,and HMIPs had hydrophilic groups.The adsorption capacity of HMIPs was evaluated by equilibrium adsorption,kinetic adsorption,BET nitrogen adsorption specific surface analyze（BET）and selective adsorption.The Scatchard model showed HMIPs had high-enrichment and specificity than HNIPs,HMIPs had a class of azoxystrobin-specific recognition adsorption sites.The Langmuir isotherm indicated the adsorption of azoxystrobin by HMIPs were monolayer adsorption.The Lagergran pseudo-second-order kinetic model indicated the adsorption process of HMIPs was chemical adsorption.BET test illustrated HMIPs had bigger specific surface area than HNIPs.Selective adsorption indicated that compared with ordinary molecularly imprinted polymers（MIPs）,the adsorption capacity of HMIPs for azoxystrobin in water medium were higher,HMIPs successfully exhibited high selectivity in water medium.The hydrophilic molecularly imprinted dispersive solid phase extraction（HMIDSPE）coupled with liquid chromatography（LC）for the separation and determination of azoxystrobin in cucumber was exploited.Under the optimum DSPE conditions,the HMIPs could high-efficiently extract and enrich azoxystrobin.Compare HMIPs with C18,the average recoveries of azoxystrobin from blank cucumber samples spiked at 0.1,0.5,and 1 mg·mL^-1ranged between 85.93%and 88.89%with relative standard deviations（RSD）were2.10%-4.91%（n=5）.The average recoveries of azoxystrobin that used C18 as sorbent were56.20%-60.66%with RSD were 3.22%-5.18%（n=5）.The method of HMIDSPE-LC exhibited high-efficiently separation and enrichment of azoxystrobin.This method conform the standard of azoxystrobin residue analysis.The actual samples were tested and free of azoxystrobin was detected.