Electrochemiluminescence Sensor Based On Mesosporous SiO₂ Nanospheres And Carbon Nanotubes And Its Application In Drug Testing

During the past decades, electrochemiluminescence(ECL) sensor has received considerable attention and widely applied in many important analytical fields, such as immunoassay and environmental, food and drug analysis and molecular diagnosis of disease and so on. Due to the large specific surface area, chemical reactivity and size effect, nanomaterials have been widely used as immobilized materials in the solid-state ECL sensor. Abundant luminophors Ru(bpy)32+ are embedded into new nanomaterials, which could greatly improve the performance of ECL sensor. Solid state ECL sensor not only reduces the consumption of expensive reagent, but also simplifies experimental design. The most important virtue is that a re-generable sensor based on Ru(bpy)32+ recycled at the electrode surface during the ECL reaction is created.In this thesis, mesoporous silica nanospheres(m Si O2), multi-walled carbon nanotubes(MWCNTs), gold nanoparticles(Au NPs) and Nafion were applied for the fabrication of ECL sensors. The major contents in this thesis are described as follows: 1. A simple and sensitive ECL sensor based on mesoporous silica(m Si O2) nanospheres was constructed for the quantitative detection of matrine(MT). m Si O2 nanospheres were synthesized according to Stober method with some modification. Si O2 nanospheres were very uniform in both size and shape and were fixed by Nafion to absorb numerous luminophors Ru(bpy)32+. An ECL sensor based on Ru(bpy)32+/m Si O2/Nafion was constructed. At the same time, the electrochemistry and ECL behaviors of the modified electrodes were investigated and it was used to detect MT in Ru(bpy)32+/TPA system. Under optimized conditions, the constructed ECL sensor showed good ECL efficiency, wide linear range, low detection limit and satisfactory stability. This constructed ECL sensor could be applicable for real sample analysis. 2. A new electrochemiluminescence(ECL) sensor was constructed for the ultrasensitive detection of diphenhydramine hydrochloride(DPH) based on L-cysteine-functionalized multi-walled carbon nanotubes/gold nanoparticles(MWCNTs-Cys-Au NPs) nanocomposites. In this work, the nanocomposites were facilely synthesized by using L-cysteine as linking agent which could covalently conjugate to MWCNTs and Au NPs via amide bond and Au-S bond. Herein, the prepared MWCNTs-Cys-Au NPs was used as matrix material and fixed by Nafion toadsorb Ru(bpy)32+ on glassy carbon electrode(GCE) to provide a new ECL sensor for DPH. Then the electrochemical and ECL behaviors of the sensor were investigated. Approximate 9-fold enhancement in ECL intensity was observed after addition of DPH. By optimizing the experimental conditions, the proposed ECL sensor exhibited excellent assay performances in determination of DPH with a wide linear range(2×10-8-7.5×10-4 M), low detection limit(6.7×10-9 M), good reproducibility and acceptable stability. Furthermore, the constructed ECL sensor was used to analyze the DPH in real sample with a satisfactory result, which holds a great potential in the field of pharmaceutical analysis.