不对称变色酸双偶氮衍生物与某些非稀土元素的显色反应及其应用研究 Ⅰ.DBS-偶氮氯膦分光光度法直接测定有色金属及合金中的痕量铋

本文系统考察了九种不对称变色酸双偶氮氯膦类衍生物与铋(Ⅲ)的显色反应。并着重报道DBS-偶氮氯膦与铋反应的条件及其应用。在HClO_4—C_2H_5OH介质中,铋与上述试剂形成1:2的紫红色配合物,最大吸收波长位于639nm处,ε_(639)为9.54x10~4.铋在0—30μg/25ml浓度范围内服从比耳定律。反应酸度高,选择性好,许多常见元素可以大量共存。所拟方法不经分离可直接应用于某些有色金属及合金中痕量铋的测定。方法的回收率为96—102%,相对标准偏差小于4.5％。     

水溶液中痕量游离氯的气动电流法测定

气动电流法是适用于水溶液中痕量溶质分析的一种新方法。在试样被酸化的同时,通过氮气使游离氯转入气相,并在覆膜电极检定器上还原为Cl~-加以测定。检定池的电解质为9NH_2SO_4。厚0.5-Mil的聚四氯乙烯膜由表面粗糙化和用聚合物质处理以后,覆膜电极检定器的电流响应一般增加100倍以上。使用处理过的膜其寿命可达六个月。游离氯的检定极限在2ml试样中估计为1.0μg     

流动注射——吸光光度法测定自来水中余氯

城市自来水多采用氯化法消毒,余氯含量是自来水质量的重要指标,余氯测定是自来水厂和管网末端水质监控的例行项目.自来水中余氯的测定多采用邻联甲苯胺比色法,其使用的试剂为有毒品,对分析人员的健康不利.本文发现,在稀盐酸介质中余氯可氧化罗丹明6G使其褪色从而使吸光度降低.吸光度的降低值在一定范围内与余氯浓度呈线性关系,可用于余氯的测定.基于上述原理本文对流动注射—吸光光度法测定余氯含量进行了研究.试验结果表明,本法具有灵敏度高、选择性好、分析速     

一类新的4-取代胂酸型变色酸偶氮多卤显色剂的合成及其与稀土元素显色反应的研究

本文研究了五个结构新颖的显色剂与稀土元素的显色反应。其中的二溴羧基偶氮氯肿(CAsA-DBK)与稀土元素反应具有对比度大、灵敏度高、选择性好等优点。在0.6mol/LHClO_4介质中,不加任何掩蔽剂条件下,只与铈组稀土显色,与钇组稀土几乎不显色,是一个较有特色的铈组稀土试剂。     

PREPARATION OF POLYSULFONAMIDE/TiO2 NANOCOMPOSITES BY SOL-GEL

Polysulfonamide (PSA) was synthesized at room temperature, the polymerization based on terephthaloyl chloride and 3,3 '-diaminodiphenylsulfone in the common solvent N,N -Dimethyl-acetamide (DMAc). Polysulfonamide/titanium oxide nanocomposites were prepared by sol-gel method. Tetrabutyl titanate(TBT) was added into the polysulfonamide solution, at the same time ,some water was mixed to make the TBT hydrolyze. In the process, hydrochloric acid was used to catalyze the reaction. The polysulfonamide chemistry structure was characterized by FT-IR spectrum. Atomic force microscopy (AFM) was employed to observe the microstructure of the composite film. The thermal property was investigated by TGA.The results show that we have succeeded to synthesize the polysulfonamide, TiO2particles were well distributed in the composite film and average size was about 20 nm on average, the heat-resistance of nanocomposite was batter than the pure polysulfonamide.