Electrochemiluminescence Of Immobilized Ru(bpy)₃～(2+) And Its Application In Pharmaceutical Analysis

Electrochemiluminescence(ECL) is a producetion that Electrochemistry technique combined with Chemiluminescence. It has the inherent characteristics of Chemiluminescence such as high sensitivity, wide linear range, simplicity for instrument. Meanwhile, easy-controlling, good selectivity and the ability of analysis in-suit are its own merits. Among numerous electrochemiluminescence reagents, tris(2,2'-bipyridyl)ruthenium(â…¡)[Ru(bpy)₃²+] and its derivatives are the most widely used systems for ECL investigation and application. However, its widespread application is limited by the requirement to continuously deliver the ECL reagent into the reaction zone because the reagent is consumed, which implies high cost, complexity for instrument and pollution. Since Ru(bpy)₃²+can be electrochemically recycled, this problems can be overcome by immobilizing Ru(bpy)₃²+ on an electrode surface, which cannot only minimizes the consumption of Ru(bpy)₃²+ but also allow simpler instrumentations and improves the intensity of ECL. Therefore, developing novel approaches and materials to immobilize Ru(bpy)₃²+ for the fabrication of ECL-based sensors are the most interesting among the investigations about Ru(bpy)₃²+-ECL. The application of Ru(bpy)₃²+-ECL is widely, recently, the application of Ru(bpy)32+-ECL in pharmaceutical analysis attracts more and more analysts'interests.The purpose of our research work is finding novel approaches and materials to immobilize Ru(bpy)₃²+ for the fabrication of ECL-based sensors, moreover, discussing its application in pharmaceutical analysis.This thesis includes a review and a research secetionIn the first part, we have reviewed ECL, Ru(bpy)₃²+-ECL and its application in pharmaceutical analysis, moreover, about the approaches and materials to immobilize Ru(bpy)₃²+ for the fabrication of ECL-based sensors.The research section contains four subunits. The major contents in this thesis are described as follows:1 A novel ECL sensor with high sensitivity and long-term stability was prepared by immobilizing Ru(bpy)₃²+ in a nanoTiO2/Nafion composite films modified glassy carbon electrode(GCE) via an ion-exchange process. The electrochemical and ECL characters with the coreact, tripropylamine(TPA), in 0.1mol/L phosphate buffer medium were discussed. The electrochemical and ECL characters obtained with Ru(bpy)₃²+ immobilized in a nano-TiO2/Nation composite films modified GCE will be improved, owing to the lager surface, more chemical activities and electrocatalysis of nano-TiO2. The present ECL sensor based on the nano-TiO2/Nafion composite films was used for the determination of TPA with a remarkable detection limit of 3×10^-9mol/L(S/N=3) while the ECL sensors based on pure Nation films and Nafion-TiO2 composite films prepared by sol-gel techniques gave a detection limit of 1×10^-6mol/L, 1×10^-7mol/L, respectively. The present ECL sensor also showed long-term stability.2 The immobilization of Ru(bpy)₃²+ in a nano-TiO2/Nation composite films modified glassy carbon electrode(GCE) was described. It is found that the weak ECL single of immobilized Ru(bpy)₃²+ in 0.1mol/L phosphate buffer medium is greatly enhanced by Cetirizine Hydrochloride. Based on this finding, a high sensitive ECL method for determining Cetirizine Hydrochloride is developed. The Cetirizine Hydrochloride concentration in the range of 5.0×10(-9)～6.0×10(-6)g/mL is proportional to the enhancing ECL signal intensity, the detection limit for Cetirizine Hydrochloride is 1.4x10^-9g/mL, and the relative standard derivation was 3.4%(n=11, c=4×10(-7)g/mL). This method is used for the determination of cetirizine hydrochloride in human urine.3 It is found that the weak ECL single of immobilized Ru(bpy)₃²+ in 0.1M phosphate buffer medium is greatly enhanced by Chlorphenamine Maleate. Based on this finding, a high sensitive ECL method for determining Chlorphenamine Maleate is developed. The ECL sensor was prepared by immobilitying Ru(bpy)₃²+ in a nano-TiO2/Nafion composite films modified glassy carbon electrode(GCE) via an ion-exchange process. This ECL sensor was used for the determination of Chlorphenamine Maleate with a linear concentration range of 2×10^-8～1×10^-6g/mL, a detection limit of 6×10^-9g/mL(S/N=3) and RSD of 1.4%(n=11, c=3.6x10^-7g/mL). We compared this method with the Standard method mentionded in the Pharmacopoeia(2005, China), found that the results of this ECL method was almost consistent with the results of the Standard method.4 A novel ECL sensor was prepared by immobilizing Ru(bpy)₃²+ in the nano-MnO2-Nafion composite films modified glassy carbon electrode(GCE) via ion-exchange process. The electrochemical and ECL characters with the coreact, TPA(1μmol/L), in the 0.1 mol/L phosphate buffer medium were discussed. We used this ECL sensor for ECL determination of TPA and oxalate, the linear ranges were 6×10^-10～1×10^-4mol/L for TPA and 2×10^-8～6×10^-4mol/L for oxalate, and the detection limits were 2×10^-10mol/L, 9×10^-9(S/N=3), respectively. The relative standard derivation for the determination of TPA was 3.3%(n=11, c=1×10^-9mol/L). This ECL sensor showed high sensitivity and outstanding long-term stability compared with the ECL sensors prepared by other method, meanwhile, the preparation time was enormously shorten.