Solid State Electrochemiluminescence Sensor Based On Novel Nanomaterials

During the past several decades,solid state electrochemiluminescence (ECL) sensor has received considerable attentions, has been widely applied in many important analytical science fields, such as immunoassay and environmental, food and drug analysis and molecular diagnosis of disease and so on. Due to the nanomaterial of large specific surface area, chemical reactivity and the size effect, make it widely used as immobilized materials in the solid-state ECL sensor. High concentrations of embedding and modifying of ECL compounds Ru(bpy)32+in new nanomaterials (mesoporous silica, gold nanoparticles) composite film, improves selectivity and controllability of the solid-state ECL sensor. Solid state ECL sensor doesn’t only reduce the consumption of expensive reagent, but also simplify experimental design. The most important virtue is to create a regenerable sensor based on Ru(bpy)32+recycled at the electrode surface during the ECL reaction. Main research work in our thesis are as follows:1. mSiO2nanospheres were synthesized according to Stober method with some modification. SiO2nanospheres are very uniform in both size and shape. With their benefits of large specific surface and pore volume as well as tunable pore size, we propose a regenerable solid state ECL sensor based on mSiO2nanospheres loading Ru(bpy)32+. The ECL and electrochemistry of the modified electrodes were inve-stigated with tri-n-propylamine (TPA) as the coreactant. Furthermore, due to similar structures of melamine and TPA, the mesporous SiO2nanospheres/Ru(bpy)32+based modified electrodes were used for ECL determination of melamine. The proposed ECL approach was used to analyze the melamine content in powdered milk with satisfactory results. Therefore, this provides a feasible method for the rapid deter mination of melamine in the field of food safety.2. Firstly, gold nanoparticles were prepared according to sodium citrate reduction method, then novel AuNPs functionalized halloysite nanotube (fHNT) composites were effectively synthesized by electrostatic interactions, finally used for electro chemical sensing applications.The AuNPs-HNT nanocomposites were characterized by transmission electron microscopy, field emission scanning electron microscopy, zeta Potential and UV-Vis spectroscopy.The AuNPs-HNT-based modified electrode displayed high electrocatalytic reduction to the detection of hydrogen peroxide (H2O2). The proposed sensor was used to successfully detect H2O2in sterilized milk sample. Furthermore, the Ru(bpy)32+/AuNPs-HNT/Nafion composite film modified electrode exhibited good electrochemiluminescence activity for determining tripropylamine. Therefore, the AuNPs-HNT nanocomposites could be developed as a novel sensing platform for the construction of various nonenzyme biosensors and solid-state ECL sensors.3. Using organic template agent, the crystallization method, nano-sized ZSM-5zeolite was synthesized.In addition, different Si/Al ratio of ZSM-5was prepared by adjusting the ratio of aluminum and silicon(ZSM-5A、ZSM-5B、ZSM-5C、ZSM-5D). Electrochemical and electrochemiluminescence (ECL) behaviors of Ru(bpy)32+/ZSM-5/Nafion modified electrodes were studied. The results show that the greater ECL Intensity of high molar ratio of Si/Al for the determination of tripropylamine in solution. The results mostly attributed to improve diffusion of electroactive cations into Nafion via the use of Nafion-ZSM-5(high silica content of nanoparticle). That is, the improved accessibility of these ion-exchange sites coupled with the faster uptake of reagents into these materials will be of benefit to ECL intensity.Ru(bpy)32+/ZSM-5D/Nafion modified electrode was used for ECL determination of tri-n-propylamine(TPA). Modified electrode also showed high sensitivity and stability, mainly resulted from the high surface area and special pore structure of the ZSM-5D.