Ammonia-sensitive Sol-Gel Fluorescent Films Made of Organically Modified Silicates
- 化学化工－已发表论文 
研究了基于有机杂化硅氧烷的氨光化学传感器 ;实验通过四甲氧基硅烷(TMOS)和二甲基二甲氧基硅烷(DiMe_DMOS)的缩聚 ,获得以氨基荧光素(AF)为荧光指示探针 ,对氨有灵敏荧光响应的溶胶 -凝胶敏感膜 ;实验考察了溶胶先驱体、各种比例杂化硅氧烷在玻璃支撑体上成膜后对体系 pH、NH3 浓度和响应时间的变化规律 ,发现DiMe_DMOS含量的变化改变杂化膜的极性 ,并使得敏感膜对NH3 有高荧光响应值 ,而对体系的pH不响应 ;实验结果表明在pH8.4 ,0.1mol/L磷酸盐缓冲溶液中 ,氨质量浓度与其相应的荧光强度在0.5～60mg/L范围内呈良好的线性关系 ,敏感膜对NH3 的95 %响应时间为4min ,常见的共存物质如氨基酸、胺和金属离子对NH3 测定未见有明显的干扰A photochemical sensor for the determination of ammonia consisting of organically modified silicates (ormosils) was developed. Ammonia- sensitive fluorescent sol-gel films were prepared by co- condensation of tetramethoxysilane (TMOS) and dimethyldimethoxysilane (DiMe- DMOS) in the presence of aminofluorescein and γ_[(2,3)_epoxypropyl]propyltrimethoxysilane (GOPS). The gel precursors with various ratios of alkylalkoxysilanes (ormosils) were deposited on glass supports and characterized in terms of their responses to pH, NH3 and time. It was found that introduction of DiMe- DMOS into the silane mixture influenced the polarity of the modified film and made the film having a high fluorescent response to ammonia but no response to pH changes. The hybrid film exhibits the most promising properties - sensitive to ammonia and insensitive to proton ions. The experimental results showed a linear range of ammonia concentrations from 0.5 to 60 mg/L in a buffer of 0.1 mol/L phosphate at pH 8.4. The response time(95%) for ammonia is 4.0 min. No significant interference of the common coexi_sting compounds, such as amines, amino acids and metallic ions, was observed on the determination of ammonia.