Molecularly Imprinted Electrochemical Sensor For Cyhexatin Detection And Its Application

Organotin pesticides(OTP)are one of the common organometallic pesticides,which are widely used in agricultural production as the acaricides and fungicides.Curerent analytical methods for the OTP mainly depend on the gas chromatography(GC)and liquid chromatogram(LC)coupled with different detectors,which can not meet the demand of rapid detection of OTP in complicated agricultural products.Molecular imprinted polymers are excellent sensing recognition elements with unique antijamming capability and high selectivity.And they could be synthesized into various functional sensors by combining with other nano materials.In this study,electrochemical deposition,self-assembly technique and electrospinning technique were applied to synthesize OTP molecular imprinted specific recognition film and the electrospinning molecular imprinting electrochemical sensor,integrating the highly sensitive nanomaterials and disposable SPCE.The propsed assay realized the rapid detection of organotin pesticide in agricultural products.The main contents are as follows:(1)Molecularly imprinted sensitive film for specific recognition of CYT was developed using the self-assemble and electro-polymerization,using O-ATP as functional monomer,and CYT as template.The characteristics of adsorption and electrochemical behavior were studied via electrochemical methods,infrared,ultraviolet spectrum and so on.Under optimized condition,imprinted sensor presented a satisfactory linearity with the concentrations of CYT in the range of 0-800 ng/mL,and the limit of detection(LOD)was 0.26 ng/mL.Good performance was showed in the evaluation of actual samples,and the method could be applied to the determination of CYT in the pear samples.(2)Functional working electrode(AuNPs/ERGO/SPCE)was developed via electrochemical deposition of nanogold and electrochemical reduction of graphene oxide.Molecularly imprinted screen printing sensor for specific recognition of CYT was synthesized by electro-polymerizing on the AuNPs/ERGO sensing interface.The surface morphology,electrochemical behavior and recognition mechanism were studied by SEM and electrochemical methods,and the optimal conditons were obtained.The imprinted sensors presented a good linearity with the concentrations of CYT in the range of 1-500 ng/mL,and the LOD was 0.20 ng/mL.The sensitivity was well increased by hybrid nanomaterials,and the imprinted sensor possessed short response time and excellent practicality.(3)Molecularly imprinted electrochemical sensor based on AuNPs/ERGO sensing film was developed by electrospinningusing PVA as electrospinning carrier material.And the electrospinning parameters and the ratio of PVA and molecularly imprinted polymers were studied.The results showed that,this imprinted sensor presented a satisfactory linearity with the concentrations of CYT in the range of 0-800 ng/mL,the LOD was 0.17 ng/mL,and the detecting time was 15 min.The recoveries of different concentrations of CYT in real samples were from 76.0% to 90.0%,with the RSD<16.0%,which could be applied for the determination of CYT in pear samples.