Research Of Molecular Imprinted Electrochemical Sensors Of Four Weak UV-absorbing Active Components

Based on the advantages of high selectivity,high sensitivity,simplicity,speed,and economy of molecularly imprinted electrochemical sensors modified by nanomaterials,we have prepared several molecules with weak ultraviolet light absorption capacity（artemisinin,dihydroartemisinin,The erythromycin and kanamycin）imprinted electrochemical sensors have optimized the preparation and application conditions of the sensors,and characterized the morphology and performance of the prepared sensors by electron microscopy and electrochemical methods.The details are as follows:1.Based on chitosan（CS）which has better functions of dispersing graphene and nano-TiO₂ and stabilizing the modified material on the surface of the glassy carbon electrode and improving the current signal,we introduced chitosan as a modifier.The chitosan solution of graphene（Gr）and the chitosan solution of TiO₂ were sequentially modified on the surface of the glassy carbon electrode（GCE）,and then acrylamide（AM）was used as the functional monomer to polymerize a layer of green on the modified electrode in situ Artemisinin molecularly imprinted membrane,developed an artemisinin molecularly imprinted electrochemical sensor based on graphene and TiO₂layer modification（ART-MIM/TiO₂@CS/G@CS/GCE）.The results show that under optimized conditions,ART-MIM/TiO₂@CS/G@CS/GCE has a high affinity for artemisinin,and the detection range is 1.0?10^-9?2?10^-4 mol/L,the detection limit（calculated by 3 times the signal-to-noise ratio）reached 8.9?10^-10 mol/L,used for the determination of artemisinin in the actual sample of veterinary artemisia annua L.,and the recovery rate was Between 96.3%and 100.8%,the RSD value is within 6.0%.2.In order to obtain an electrochemical sensor with high sensitivity and high selectivity to dihydroartemisinin,carboxylated carbon nanotubes doped with polyethyleneimine（PEI）,we prepared a composite nanomaterial PEI@MWCNT-COOH,And use it as a sensitizing material to modify the glassy carbon electrode,and then prepare the dihydroartemisinin molecularly imprinted film on the modified electrode by in-situ polymerization method,and obtain the dihydroartemisinin molecular imprint based on PEI@MWCNT-COOH Electrochemical sensor（DHA-MIM/PEI@MWCNT/GCE）.The detection range of this sensor for dihydroartemisinin is 8.0×10^-78.0×10^-5 mol/L,and the detection limit（calculated by S/N=3）is 3.6×10^-8 mol/L.In the determination of dihydroartemisinin in veterinary Artemisia annua L.,the recovery rate of the spiked standard is between 95.3%and 100.3%,and the RSD value is below 5.0%.3.Selecting carbon nanohorns（CNHs）and polydopamine（pDA）as modified materials,modifying the carbon nanohorns whth drop coating on the surface of the glassy carbon electrode（GCE）firstly,then the polydopamine was modified by electropolymerization,and then 2-aminopyridine（2-AP）is a molecularly imprinted membrane of erythromycin modified by electropolymerization.We prepared a molecularly imprinted electrochemical sensor based on carbon nanohorn and polydopamine（Ery-MIM/pDA/CNHs/GCE）.Under optimized conditions,the detection concentration range of the sensor for erythromycin is 1.0×10^-51.0×10^-8,and the detection limit is 2.7×10^-9 mol/L（S/N=3）.The RSD of erythromycin detection in pork and eggs is within 6.0%,and the recovery rate of spiked standard is between 95.4%and 102.5%.4.In order to obtain a highly sensitive and selective kanamycin（KAM）molecularly imprinted electrochemical sensor,we deposited graphene oxide on the surface of the glassy carbon electrode by electroreduction,and then electropolymerized 2-aminopyridine（2-AP）On the surface of the glassy carbon electrode modified with reduced graphene oxide,and finally using dopamine as the polymerization monomer,a layer of molecularly imprinted membrane of kanamycin was modified on the above electrode by electropolymerization method.Molecularly imprinted electrochemical sensor（KAM-MIM/pAP/rGO/GCE）.The sensor has good stability and reproducibility.The detection range of kanamycin sulfate is 2.0×10^-72.0×10^-4,and the detection limit is 7.0×10^-8 mol/L.The RSD for the detection of kanamycin in the actual samples of eggs is within 4.0%,and the recovery rate of the spiked standard is between 98.1%and 100.6%.