【作者】 闫良国；

【导师】 杜斌；

【作者基本信息】 南京工业大学 ， 应用化学， 2002， 硕士

【摘要】 本文详细地叙述了微乳液的定义、分类、微观结构、制备、性质和在分析化学方面的应用概况，概述了三羟基荧光酮类试剂的结构、离解平衡以及与金属离子的配合位置和配合物的结构。实验中选取以苯基荧光酮为母体、具有不同取代基和取代基在不同位置上的苯基荧光酮（PF）、二溴羟基苯基荧光酮（DBH-PF）、三甲氧基苯基荧光酮（TM-PF）、邻氯苯基荧光酮（o-CPF）、邻硝基苯基荧光酮（o-NPF）、间硝基苯基荧光酮（m-NPF）和对硝基苯基荧光酮（p-NPF）等三羟基荧光酮类化合物为显色剂，系统地研究其在微乳液介质中与Ga³⁺、In³⁺、Co²⁺、Ni²⁺等金属离子的显色反应条件（介质、酸度、微乳液用量、显色剂用量、稳定时间、配合比、摩尔吸光系数等）。实验结果表明，7种显色剂均能在微乳液介质中与金属离子Ga³⁺、In³⁺、Co²⁺、Ni²⁺发生反应，生成稳定配合物，其与Ga³⁺、In³⁺的反应在酸性（pH4.94～5.90）介质中进行，最大吸收波长在560nm～580nm之间；而与Co²⁺、Ni²⁺的反应在pH9.20～10.38的碱性介质中进行，λ_max在620nm～650nm(Co²⁺)和590nm～606nm(Ni²⁺)之间。灵敏度均较高，表观摩尔吸光系数在（7.17×10⁴～3.23×10⁵）L·mol^-1·cm^-1之间。并应用于实际样品的分析测定，取得了满意的结果。 选用水溶性相对较差的显色剂苯基荧光酮（PF），测定了它在不同胶束、微乳液相和水相间的分配系数，验证了微乳液的增溶增敏作用。从机理上详细地讨论了显色剂结构对显色性能的影响以及微乳液介质对显色体系的增溶增敏作用。 实验结果表明，显色剂的结构对其显色性能有着重要的影响，具有较高电负性的溴原子和强供电子基团三甲氧基能够改变整个显色剂分子的电子云分布，使分子的共轭体系程度增加，π电子流动性增强，使反应官能团羟基上的质子较易离去，增加了试剂与金属离子的配位能力；而吸电子基团虽然也能使分子的共轭体系程度增加，但由于存在诱导效应，而使其与金属离子反应的灵敏度有所下降；在9-苯环的邻、间、对位置上引入硝基后的显色剂与金属离子反应的灵敏度依次降低，这是由于间位的硝基不参与共轭体系所致。 研究结果还表明，微乳液对显色体系具有更好的增溶增敏作用，在微乳液中，助表面活性剂（直链醇）存在于胶束的界面，它与表面活性剂一起形成膜相，使胶束界面具有更好的极性，从而使得微乳液中胶束界面上以吸附形式存在的显色剂有所增加。油相存在于胶束的内核，使胶团的体积变大、胶束界面面积增加、胶束栅层空间增大，从而使显色剂容易在胶束的栅层得到增溶。K_D的测定结果表明，显色剂在微乳液中有更大的增溶量和更高的富集程度，其表观上表现为显色剂在微乳液中有较大的分配系数和显色体系有较高的摩尔吸光系数，从而验证了增溶增敏是协同产生的。更多还原

【Abstract】 In this paper, the definition, classes, microstructure, preparation and properties of micromulsion have been reported in detail, as well as its application to analytical chemistry. The structure, dissociation equilibrium of tri-hydroxyl fluorone reagents and the complex structures between fluorone and metallic ions are also summarized. Color reactions of metallic ions (Ga3+, In3+, Co2+, Ni2+) with series of substitution derivates of tri-hydroxyl phenyl fluorone (PF, DBH-PF, TM-PF, o-CPF, o-NPF, w-NPF, p-NPF) were conducted in the presence of micromulsion media. The effects of different conditions such as media, pH value, etc on the color reactions have been researched. The results show that in the micromulsion media the above seven types of color reaction reagents can compound with Ga3+, In3+, Co2+ and Ni2+ stably and the formed complex have highly sensitivity with apparent molar absorptivity of (7.17× 104~3.23×105) L-mol-1cm-1. Reactions with Ga3+ and In3+can be conducted in acidic media (pH 4.94-5.90), which can produce complex with λmax between 560-580 nm. Reactions with Co2+ and Ni2+ can be conducted in alkaline media (pH 9.20-10.38), which can produce complex with X max between 620-650 nm (Co2+) and between 590-606 nm (Ni2+). Above methods have been applied to the determination of metal ions with satisfactory results.The distribution coefficients (KD) of PF (which has lower water solubility) between phases of micelle, microemulsion and water have been determined. The solubilization and sensitization of microemulsion to the reactions are also been validated.In terms of experimental results, the structures of fluorone reagents have important influence on their color reaction abilities. Electron-donating substituting groups make protons of reactive groups dissociate easily, and increase complex ability of fluorone reagents with metallic ions. However, electron-withdrawing groups reduce such complex ability and sensitivity because of its inducement effect. The effect of nitryl substitution group on the color reaction abilities of phenyl fluorone derivates has also been discussed.From the experiment, it is clear that microemulsion media have more excellent solubilization and sensitization effect on the color reactions than other media. In the microemulsion media, consurfactants (straight chain alcohol), which locate on the surface ofmicelle, can effectively improve polarity of micelle interface and increase adsorption amounts of color reaction reagents. Oil (alkane), which lies in the core of micelle, can directly expand the bulk, surface and barrier space of micelle. Hence, color reaction reagents will be easily caught at the places of surface and barrier of micelle. The determination results of KD have indicated that microemulsion media have higher effect on the solubilization and enrichment of color reaction reagents than other media. Highly apparent KD and molar absorptivity proves that solubilization and sensitization are cooperating.更多还原