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Studying On A CdTe Quantum Dots Electrochemiluminescent Sensor Based On Carbon Nano-tubes Supporting

Posted on:2012-06-02Degree:MasterType:Thesis
Country:ChinaCandidate:C X YuFull Text:PDF
GTID:2218330368992980Subject:Analytical Chemistry
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This paper studied the electrochemiluminescent (ECL) of CdTe quantum dots (QDs) on ITO working electrode in alkaline solution. Because of the ECL energy transferred excited CdTe QDs to quencher is proportional to the concentration of quencher, we established a novel methodology for detection of catechol derivatives. And based on it, we could fabricate a sensor, which can detect the lower concentration of samples with desired stability.The first part studied the synthesis of CdTe QDs and investigated the influence of different preparation conditions on the quantum yield. Through changing the ratio of stabilizer thioglycolic acid(TGA), concentration of reactants, ratio of Cd2+ /HTe- and the pH, we obtained different sizes of QDs with good stability, high quantum yield and narrow full width half-maximum(FWHM). By investigating the synthesis, we found that when TGA/CdCl2=1.3, CdCl2/HTe-=4, pH=9, CCd2+=20mM, we got QDs at long wavelength with higher quantum yield.The second part studied the ECL mechanism of CdTe QDs using ITO as working electrode in the alkaline solution. The results indicated the phenomenon that ECL of CdTe QDs on the ITO electrode could occurre under a lower voltage, and ITO was cheaper and more convenient. Since the ECL of CdTe QDs in aqueous is weak and unstable, we took some actions to improve it. Although the intensity and stability of ECL get improved and it can detect dopamine (DA), yet the process is trouble, so to modified CdTe QDs on the ITO electrode and increase the intensity and stability of ECL, became our next goal.The third part studied the fabrication of CdTe QDs electrochemiluminescent sensor. Through mixing CNT, CHIT and CdTe quantum dots at certain ratio and after Infrared heat treatment, we casted the composite solution on ITO electrode, the ECL intensity increased significantly and the stability greatly improved. An ECL-based DA sensor is developed which signaled with CdTe QDs. The ECL energy transfer from the excited CdTe QDs to quencher produced a novel methodology for detection of DA. The ECL-based sensor showed excellent character for DA measurement. Its linear detection limit decreased to 1×10-10mol/L. Based on it, this CdTe QDs ECL sensor could be used to detect catechol derivatives with desired result and good stability.
Keywords/Search Tags:Electrochemiluminescence, CdTe QDs, sensor, CNT, Indium tin oxide(ITO)
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