Development of novel catalytic methods of analysis for trace characterization

为了获得环境中微量元素的含量、存在状态、分布和循环等信息，需要灵敏、选择性强的分析方法。基于催化反应的动力学分析方法因其极高的灵敏度、低的检测限和选择性而被用于各种元素的痕量分析。通过使用催化动力学分析方法，可以很容易地测定低至10^<-9>- 10^<-11>M的金属离子。流动注射分析（FIA）与催化方法相结合，可以获得更高的精度和更快的样品通量。因此，我们开发了动力学催化分析方法的铁（II，III），钴（II），铜（II），钒（IV，V）和亚硝酸根离子的流动注射方法。本工作所用的指示反应如下：a）3-甲基-2-苯并噻唑啉酮腙（MBTH）与N，N-二甲基苯胺（DMA）和/或改性Trinder试剂对Fe（Ⅱ，Ⅲ）和/或Co（Ⅱ）的氧化偶联反应，B）N-苯基对苯二胺与DMA对Cu（Ⅱ）和/或间苯二胺对NO_2的氧化偶联反应<2->，c）过氧化氢氧化3，3 ′，5，5 ′-四甲基联苯胺（TMBZ）用于Fe（II，III），d）N-3-磺丙基-TMBZ的溴酸盐氧化用于V（IV，V），e）MBTH的过氧化氢氧化用于Fe（II，III）和f）铁（III）与半胱氨酸在phen存在下的氧化还原反应用于Cu（II）。进一步提高动力学-催化方法灵敏度的可能性之一是活化剂的应用。Phen、sulfosulycylate和Tiron分别对Fe（II，III）、V（IV，V）和Co（IJ）的催化活性有较好的活化作用。该方法已成功地应用于天然水样和标准物质的测定。

In order to obtain the information on the amount, existing state, distribution, and circulation of trace elements in environment, the sensitive and selective methods of analysis are still desired. Kinetic methods of analysis based on catalytic reactions have been utilized to trace analysis for various elements because of their extremely high sensitivity, low limit of detection and selectivity. By using the catalytic-kinetic methods of analysis, as little as 10^<-9> - 10^<-11> M of metal ions can easily be determined. The adaptation of flow injection analysis (FIA) to catalytic methods can lead to many advantages such as higher precision and rapid sample throughput. We thus developed the kinetic-catalytic methods of analysis for iron(II, III), cobalt(II), copper(II), vanadium(IV, V) and nitrite ions by FIA methods. Indicator reactions used in this work are as follows : a) Oxitative coupling reaction of 3-methyl-2-benzothiazolinone hydrazone (MBTH) with N,N-dimethylaniline (DMA) and/or modifies Trinder's reagent for Fe(II,III) and/or for Co(II), b) Oxidative coupling reaction of N-phenyl-p-phenylenediamine with DMA for Cu(II) and/or m-phenylenediamine for NO_<2->, c) Hydrogen peroxide oxidation of 3,3', 5,5'-tetramethylbenzidine (TMBZ) for Fe(II, III), d) Bromate oxidation of N-3-sulfopropyl-TMBZ for V(TV, V), e) Hydrogen peroxide oxidation of MBTH for Fe(II,III) and f) Redox reaction of iron(III) with cysteine in the presence of phen for Cu(ll). One of the possibilites for further increasing the sensitivity of the kinetic-catalytic methods is the application of activators. Phen, sulfosulycylate and Tiron acted as effective activators for the catalysis of Fe(II, III), V(IV,V) and Co(IJ), respectively. These methods have been successfully applied to the determination of natural water samples and reference materials.