The Investigation And Analytical Application Of Electrochemiluminescence Systems With Silica Sol-Nano-Au Modified Au Electrode

Based on the summary of relevant research at home and abroad, the Silica sol/Nano-Au composite material applied to the gold electrode modified and luminescentreagent Ru(bpy)32+fixed, developed a variety of electrochemical luminescence sensors.The specific research contents and conclusions include:1. The electrochemilumine (ECL)scenceintensity of Ru(bpy)32+could be enhanced inthe presence of matrine and an ECL method was therefore established for determination ofthe matrine at gold electrode．The electrochemical and ECL behaviors of this system werestudied．In PBS buffer solution(pH8.0), the ECL peak counts increased linearly with theincrease of the concentration of matrine in the range of1.5×10-7~1.5×10-4mol/L atscanning rate of100mV/s with a linear correlation coefficient of0.9989. The detectionlimit for matrine was5.65×10-9mol/L and the RSD for10replicate determinations of1.5×10-5mol/L matrine was4.01%．The results of recovery tests indicated that therecovery was92.5~101.4%and the RSD was2.86%(n=5)．The proposed method showedhigh selectivity, sensitivity and simplicity, and was applied to the analysis of matrinetablet with satisfactory results．2．For the further study of the electrochemical and ECL behaviors of matrine on thechemically modified gold electrode. The Silica sol/Nano-Au/PVA/L-Cysteine modifiedgold electrode was prepared. In the presence of matrine, the ECL intensity of Ru(bpy)32+on the modified electrode was enhanced significantly. In view of the above, a newelectrochemiluminescence method for the determination of matrine was established.Under the optimum condition, the calibration curve showed a good linearity over matrineconcentration in the range of1.5×10-7~1.5×10-4mol/L(r2=0.9984) and the detectionlimit(S/N=3) was5.22×10-10mol/L, the modified electrode of the detection limit wasreduced by an order of magnitude r than the bare electrode．The RSD for8timesdetermination of1.5×10-5mol/L matrine was1.41%. The results of recovery testsindicated that the recovery was97.6~102.1%and the RSD was1.77%(n=5). The proposedmethod showed high selectivity and sensitivity, and was applied to the analysis of matrinein tablet with satisfactory results.3．The Silica sol/Nano-Au/PVA/L-Cysteine/Ru(bpy)32+modified gold electrode wasprepared. The electrochemical and electrochemiluminescence characteristics of Ru(bpy)32+which fixed in the modified gold electrode was studied, founded that sulpiride onRu(bpy)32+electrochemical luminescence with strong enhancement effect. Accordingly,the electrochemiluminescence sensor of sulpiride was developed. Under the optimumcondition, the calibration curve showed a good linearity over matrine concentration in therange of1.0×10-6~1.0×10-4mol/L(r2=0.9954)and the detection limit(S/N=3) was2.18×10-9 mol/L．The RSD for8times determination of1.0×10-5mol/L matrine was2.71%. TheSilica sol/Nano-Au/PVA/L-Cysteine/Ru(bpy)32+modified Au electrode can be applied tothe determination of sulpiride in tablet samples with satisfactory results. The recoverieswere between97.6and102.1%. The results clearly showed that Au nanotubes possessedan excellent electrocatalytic activity, also could accelerate electron transfer rate betweenthe redox-active Ru(bpy)32+and the electrode. The results showed that the proposedmethod was sensitive for the determination of sulpiride．4．The Silica sol/Nano-Au/PVA/L-Cysteine/Ru(bpy)32+composite film modified goldelectrode was prepared. Founded that azithromycin on Ru(bpy)32+electrochemicalluminescence with strong enhancement effect, which fixed in the modified gold electrode.Accordingly, the electrochemiluminescence sensor of azithromycin was developed.Contrasted PVA and PVP as helping membrane agent effection on ECL Intensity, theresults show that the modified electrode has good electrochemical activity andelectrochemiluminescence (ECL) response and PVP is more conducive to the stability ofthe membrane and luminous intensity enhancement. Under the optimum experimentalcondition,the linearity of azithromycin concentration to ECL intensity was achieved inthe concentration of azithromycin of1.0×10-7~1.0×10-4mol/L and the detectionlimit(S/N=3)was1.35×10-9mol/L．The RSD for8times determination of1.0×10-5mol/Lazithromycin was1.85%．The sensor has been applied to the analysis of azithromycin inmedicinal with recovery ranging from97.9to101.6%.