Preparation of an Electrochemical Sensor Based on L-cysteine/CdTe Quantum Dots Modified Electrode and Its Detection of Lead Ions
  
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KeyWord:CdTe QDs  L-cysteine  modified electrode  electrochemical sensor  lead ions
  
AuthorInstitution
XU Shi-chao,ZHANG Yi-yi,DONG Kai,WEN Jun-nan 1.天津工业大学环境与化学工程学院;2.天津工业大学中空纤维膜材料与膜过程省部共建国家重点实验室;3.天津工业大学水质安全评价与保障技术工程中心
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Abstract:
      A simple and sensitive electrochemical sensor was fabricated for the detection of Pb2+ based on L-cysteine(L-Cys)/CdTe quantum dots(QDs) hybrid nanocomposites modified gold electrode(GE).CdTe QDs were synthesized in aqueous phase.Then,carboxyl labeled CdTe QDs were covalently bonded to L-cysteine on gold electrode,depending on connection between-COOH on MPA-CdTe surface and —NH2 in L-cysteine.The morphology and composition of CdTe QDs and hybrid nanocomposites were characterized by fourier transform infrared spectroscopy(FTIR),X-ray powder diffraction(XRD),transmission electron microscopy(TEM),UV-Vis and fluorescence spectrometry.The electrochemical performance of L-Cys/CdTe nanocomposite and the optimized self-assembly time of CdTe QDs on electrode were investigated by cyclic voltammetry(CV).The electrochemical behavior of lead ions at L-Cys/CdTe nanocomposite modified gold electrode was investigated by different pulse stripping voltammetry(DPSV).Under the optimal hybridization conditions,different pulse stripping voltammetric responses of L-Cys/CdTe/GE sensor were in linearity with Pb2+ in the concentration range of 1.0×10-6-1.0×10-2 mol/L with a detection limit of(3σ,n=5) 4.0×10-7 mol/L and a correlation coefficient(r2) of 0.993 8.Therefore,the electrochemical sensor modified with L-Cys/CdTe/GE nanocomposites exhibited the advantages of high sensitivity,good reproducibility and stability,providing a potential platform for the fabrication of other electrochemical sensors.
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