〔I_2Br〕^-与某些碱性三芳基甲烷染料的水相显色反应及其应用于碘的分光光度测定  

Spectrophotometric Determination of Iodide with 〔I_2Br〕^--Basic Triarylmethane Dye System in Aqueous Solution

作　　者：吕明玉[1] 刘绍璞[2] 

机构地区：[1]重庆渝州教育学院 [2]西南师范大学环境化学研究所,重庆400715

出　　处：《分析化学》2001年第3期323-326,共4页Chinese Journal of Analytical Chemistry

摘　　要：研究〔I2 Br〕-络阴离子与乙基紫、结晶紫、维多利亚蓝 4R等碱性三芳基甲烷染料在聚乙烯醇存在下的离子缔合反应的条件、分光光度特征和分析化学性质。结果表明 ,在稀磷酸介质中 ,当形成上述离子缔合络合物时 ,溶液均发生明显的颜色变化。不同染料体系的摩尔吸光系数在 2 .6× 10 4 ～ 6 .2×10 4 L·mol-1·cm-1之间 ,以乙基紫体系灵敏度最高。碘离子浓度在 0～ 1.6mg/L(乙基紫体系 )、0～ 1 4mg/L(结晶紫体系 )和 0～ 0 .8mg/L(维多利亚蓝体系 )符合比耳定律 ,可用于水相直接显色测定碘离子。方法也有良好的选择性 ,较大量的其他卤离子、一些无机酸根以及一定量的常见金属离子不干扰。用于海带、紫菜和黄豆中碘离子的测定 ,结果较为满意。The reaction conditions, the spectrophotometric characteristics, and the analytical properties of the ion-association complex of 〔I 2Br〕 - with the basic triarylmethane dye such as ethyl violet (EV), crystal violet (CV), and victoria blue 4R (VB4R) in the presence of polyvinyl alcohol (PVA) were studied. The results showed that the color of the solutions would change obviously when the above ion-association complexes were formed in dilute phosphoric acid solution. The molar absorptivities (ε) of different systems are between 2.6×10 4 and 6.2×10 4 L·mol -1 ·cm -1 . The sensitivity of the ethyl violet system is the highest among them. Beer′s law is obeyed in the range of 0～1.6 mg/L I - for ethyl violet system, 0～1.4 mg/L for crystal violet system, and 0～0.8 mg/L I - for victoria blue 4R system, respectively. The method can be applied to direct determination of iodide in aqueous solution. The method has good selectivity. A large amounts of halide ions, some other inorganic acid group ions and amount of common metal ions don′t interfere the determination of I -. This method was used to determine I - in kelp, laver and soy bean with satisfactory results.

关 键 词：碘离子 分光光度法 碱性三芳基甲烷染料 溴化钾 亚硝酸钠 测定方法 海水 紫菜 黄豆 

分 类 号：O657.3[理学—分析化学]