| Electrochemiluminescence?ECL?is a technique that can initiate light radiation during the high-energy electron-transfer reactions occurring at the surface of working electrode in electrochemical processes.ECL has received increasing attention in many fields,including environmental pollutant determination,pharmaceutical analysis and immunoassays,because of its advantages of high sensitivity,wide linear range,simple operation and controllability.Molecular imprinting technique is a unique technique used for preparing polymers with synthetic recognition sites that have a predetermined selectivity for analytes of interest.The molecularly imprinted polymers?MIPs?have been utilized as materials of molecular recognition in many scientific and technical fields,such as solid-phase extraction,chromatographic separation and drug releases.It has the advantages of high selectivity,good stability and excellent life expectancy.This paper developed two molecularly imprinted electrochemiluminescence?MIP-ECL?sensors based on the selectivity of MIPs and the sensitivity of ECL for the determination of ochratoxin A?OTA?.In addition,CdTe quantum dots?QDs?can enhance the ECL intensity of Ru?bpy?32+-tripropyl amine?TPrA?system,we developed the CdTe-Ru?bpy?32+-TPrA system for the detection of OTA.The main contents and results are summarized as follows:?1?The research of OTA/MIP/Ru?bpy?32+/MWCNTs/Nafion/GCE ECL sensorRu?bpy?32+ was immobilized on the electrode surface as the luminescent material by nafion and MWCNTs based on the electrostatic incorporation.Then the MIPs of OTA was dropped on the surface of Ru?bpy?32+/MWCNTs/Nafion/GCE to obtained MIP/Ru?bpy?32+/MWCNTs/Nafion/GCE.The process of template elution and rebinding acted as a gate to control the flux of probes,which passed through the cavities and reacted on the electrode surface.When the imprinted film was rebound with OTA,the ECL signal decreased.Under the optimal conditions,the MIP/Ru?bpy?32+/MWCNTs/Nafion/GCE ECL sensor showed wide linear to the concentration of OTA in the range from 0.1 to 10 ng·mL-1 with a detection limit?S/N = 3?of 0.03 ng ·mL-1.Corn samples were assayed by using this sensor,and the recoveries ranging from 95.2%to 102.7%were obtained.?2?The research of OTA/MIP/RuSi/GCE ECL sensorThe RuSi NPs were synthesized by a typical W/O micromulsion route.The sensor was fabricated by remodification of RuSi/CS with a thin film of molecularly imprinted polymer,which provided the specific binding sites for OTA.The ECL intensity decreased with the OTA molecules reboud in MIP.The ?IECL depended linearly on the logarithm of the OTA concentration in the range from 0.1 pg·mL-1 to 14.76 ng·mL-1 with lower detection limit of 0.027 pg·mL-1?S/N = 3?.The MIP-ECL sensor enabled the successful application of this method to determine OTA in corn.?3?The research of OTA-CdTe-RuSi-TPrA ECL energy transfer sensor.In this part,the ECL of MIP/RuSi/GCE was researched futher in the solution of CdTe QDs.And the results showed that the UV-vis absorption spectrum of CdTe QDs had a spectral overlap with the ECL spectrum of RuSi NPs,which made it possible for the energy transfer from excited-state luminophore RuSi*to CdTe and exhibited signal amplification.Under the optimal conditions,the ECL decrease value depended linearly on the logarithm of the OTA concentration in the range from 1.00×10-5 to 11.13 ng·mL-1 with lower detection limit of 3.0 fg·mL-1?S/N = 3?.This ECL sensor has also been applied to detect OTA concentration in the real samples with satisfied results,and the recoveries range from 85.1%to 107.9%. |
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