Studies And Applications Of Luminol Electrochemiluminescence On A Platinum-nanoparticle-modified Electrode In Neutral Aqueous Solution

Electrochemiluminescence(ECL) is a new kind of detection approach,which has been widely used in biological,pharmic,chemical and environmental applications due to its continuance,sensitivity,reproducibility and relative easiness to be automatically controlled.In ECL research,although luminol is a typical and widely used luminescent reagent,its ECL application for biological samples suffers from several problems especially the weak light emission in neutral solution.The enhancement of the luminol ECL in neutral solution has received considerable interests.Platinum nanoparticle(PtNP) is one of the most effective chemical catalysts.In the study,we modified an ITO electrode with PtNPs(PtNPs/ITO),studied the behavior of luminol ECL on the PtNPs/ITO electrode,and proposed the possible mechanism.In addition, we found a novel method to detect DDVP sensitively based on the enhancement of DDVP to luminol ECL.This thesis includes three chapters,which are summarized as follows:In chapterâ… ,the development,mechanisms of ECL and the applications of nanoparticle modified electrode in ECL have been introduced.In chapterâ…¡,we modified an ITO electrode with PtNPs using a wet chemical method.Five ECL peaks could be obtained for the PtNPs/ITO electrode in a neutral aqueous solution.The behavior of luminol ECL on the PtNPs/ITO electrode was distinctive compared with that on bulk platinum(Pt),pre-oxidized platinum(PtO),or bare ITO electrodes.The effects of potential scan direction and range,the electrolyte type,the medium pH,the concentration of oxygen in the solution and the different kinds of nanoparticles in saturated oxygen solution,were examined.Finally,a possible mechanism of luminol ECL on the PtNPs/ITO electrode was proposed.In chapterâ…¢,a novel ECL approach was proposed for the determination of DDVP based on its oxidation reaction with luminol and hydrogen peroxide in a CTAB alkaline medium.In addition to its simplicity,rapidity and satisfactory accuracy,the method afforded very high sensitivity in the determination of DDVP.Under the optimal conditions,the linear response of ECL-emission versus DDVP concentration was valid in the range 5 to 8000 ng L^-1(r² =0.9982) with a detection limit(S/N=3) of 0.42 ng L^-1.