Hot Electron Induced Cathodic Electrochemiluminescence Systems And Their Applications

Electrogenerated chemiluminescence(ECL) is a new kind of technology whichcombine electrochemistry with chemiluminescence. It has been widely used inanalytical chemistry owing to its advantages, such as easy to control, high sensitivityand excellent selectivity. As an important branch of electrogeneratedchemiluminescence, hot electron induced cathodic electrochemiluminescence (HECL)has also provoke people’s great intreast, and it has been used in the field of biologysuccesfully. In this paper, several kinds of materials have been studied for their use incathodic electrochemiluminescence, and several new luminescence systems have beensuccessfully constructed. We mainly study several noval materials of electrodes whichcould be used in cathodic electrochemiluminescence and their application. There arefour chapters in this paper.In chapter one, the overview of the development of ECL, as well as the principleand general classification have been introduced, and then special stress has been laidon the summarization of the mechanisms, luminophores and materials of workingelectrode involved in cathodic ECL. In addition, the future development of cathodicECL was also discussed. Finally, the purpose and main content of the paper wereproposed at the end of this chapter.In chapter two, the cathodic ECL of CdS nanoparticles modified screen printedcarbon electrodes (CdS-SPCEs) during cathodic pulse polarization was studied for thefirst time, and the mechanism was discussed. The electrode is of low cost, highluminous signal, low background noise and good stability. The ECL intensity isproportional to the concentration of dissolved oxygen in the range of1.7mg/L to33mg/L with the limit of detection of0.02mg/L. This method is promising to use inanalysis of biological oxygen demand.In chapter three, the carbon paste electrode is used for the first time to study theECL behavior of Ru(bpy)32+/S2O82-, and the possible mechanism of the system hasbeen proposed. A ECL method for detection of several kinds of simple phenols hasbeen realized based on the ECL quenching effect. Under the optimum conditions, thelinear relationship between the quenched ECL intensity and pyrocatechol was oberserved over the range of2×10-10mol/L～4×10-9mol/L and8×10-9mol/L～4×10-7mol/L with the limit of detection of7.7×10-12mol/L.In chapter four, the cathodic ECL behavior of luminol on Ta/Ta2O5electrode isstudied, and the luminence mechanism has been put forward. A new method for thedetection of catecholamines is constructed based on its ECL quenching effect arisingfrom the competition effect which leads to the consumption of free radical. Under theoptimum conditions, the quench ratio are linearly increased with the concentration ofepinephrine, dopamine and norepinephrine in the range of2×10-8mol/L～2×10-6mol/L,8×10-9mol/L～4×10-7mol/L and8×10-9mol/L～8×10-7mol/L with the limit ofdection of5.5×10-9mol/L,7.8×10-11mol/L and8.2×10-11mol/L, respectively.