Study On The Solid-state Electrochemiluminescence Electrode Constructed By Silica-nanoparticles Loaded With Metal Complex

Electrochemiluminescence is a kind of chemiluminescence phenomenon caused by theelectrochemical reaction. electroactive substances assimilate and convert electrochemicalpotential at the surface of an electrode via an applied potential. Luminescent signals can beobtained from the excited states of an ECL luminophore generated at electrode surfaces.luminous reagent represented by the (Ru(bpy)32+) and its derivatives are widely used in ECLassay method. Immobilization of Ru(bpy)32+on a solid surface provides several advantagesover the solution-phase ECL procedure, such as the simplicity of experimental design andcost-effectiveness. Ruthenium complexes is immobilized on the electrode surface byself-assembled film, Ion exchange and Covalent interraction or sol-gel. In fact, although manyneutral Ir(III)complexes have been demonstrated to display high ECL effciencies in organicsolutions usually with a degree of efficiency much higher than Ru(bpy)32+, their applicativefield has been restricted by their very poor water-solubility. The methods of Ion exchange andCovalent interraction don‘t work, because the neutral iridium complex hasn‘t charged andfunctional group which may be covalently. Becanse of the colorless, easy modification,silica nanoparticles employed as metrices, by doping, cladding, adsorption methods is widelyused to load fluorescent dye, medicine, metal complexes and megnetic beads.So the paperfocused on the immobilization method of Iridium or ruthenium complex loaded with silicananoparticles.The capability of the solid–state electrode applied to the analytical detection isevaluated.First, we prepared Ru(bpy)32+-entraped silica nanoparticles (Ru(bpy)32+@SiNP)according to the hydrolysis and polymerization reaction of tetraethoxysilane (TEOS) in thepresence of alkali.The reaction was carried out in a microemulsion (W/O) system, where themicroemulsion system acts as small droplets to modulate the particle size of theRu(bpy)32+@SiNP. The particle sizes of the as-prepared nanoparticles are around100nm. Theinfluence of alkali catalysts on the particle size was discussed. Electroplating the glassycarbon electrode which was modified with oxide graphene by the method ofelectro-deposition is quasi reversible electrode. Chitosan was self-assembled onto the surfaceof the Ru(bpy)32+@SiNPs modified electrode. the Ru(bpy)32+@SiNP-CS modified electrodehas long lifetime. The pH of the solution and the amount of nanoparticles on the electrodehave an impact on the Ru(bpy)32+/TPA ECL system. The solid phaseelectrochemiluminescence electrode detection limit of TPA is1.0×10-11mol·L-1. The CVspectrums indicated codeine has two oxidation peaks. So Ru(bpy)32+/codeine ECL system hasdistinct reaction mechanism. Ru (bpy)32+/codeine system had high ECL efficiency. Thedetecting limit of the ECL solid-state electrode for codeine was1.0×10-10mol·L-1Senond, fluorescent dyes can be loaded with organic silica nanoparticles in directmicroemulsion system. So a novel strategy for electrochemiluminescent (ECL) chemicalsensing by making use of an electrode modified with organosilica nanoparticles (OSiNPs) thatare loaded with a ECL iridium(III) complex. Three kinds of OSiNPs have been prepared byusing vinyltrimethoxysilane, vinyltriethoxysilane, and phenyltrimethoxysilane, respectively, as the precursors. The OSiNPs were loaded with the complex Ir(pq)2(acac)(where pq standsfor2-phenylquinoline and acac for acetylacetonato) and shown to be spherical in shape,uniform, and highly monodisperse in aqueous phase. The luminescence propertie s of the Ir(III)complex remain unchanged after encapsulation. The structure of organic siloxane monomerwas the major factor that affected the size distribution of the OSiNPs. The ECL properteriesof the modified electrodes were evaluated by using2-(dibutylamino)ethanol (DBAE) as thecoreactant (analyte). The electrode prepared from phenyltrimethoxysilane as the precursorexhibited the best sensitivity for DBAE and gives a detection limit as low as4.8×10-9mol·L-1and a linear range from5.0×10-9to1.0×10-6mol·L-1. The solid phaseelectrochemiluminescence electrode also has the very good performance to the codeine,Ir(pq)2(acac)/Codeine system has a unique electrochemiluminescence mechanism.