Development of highly sensitive method for the determination of trace

以反应产物为催化剂的自催化反应是检测超痕量化学物质最有效的扩增系统之一。数学模型计算表明，对于任何催化剂的初始浓度，自催化系统在拐点处提供相同的s型反应物浓度-时间曲线，即只有拐点时间与其相关。结果表明，该方法作为一种动力学等灵敏度检测系统和理论上无限灵敏度的催化剂检测方法具有重要的应用价值。金属配合物的分解引起金属离子对自身配合物产生催化作用的放大，是实验室系统中实现自催化反应的一种模式。本实验室开发了一种新的分析方法——“动力学分异模式高效液相色谱法（KD-HPLC）”，根据对金属配合物的一些认识，我们发现惰性Co (III) -吡啶偶氮染料配合物与过氧单硫酸酯的分解是一种很好的指示反应体系，可以在磷酸盐缓冲介质中分解钴（II）离子。钴（II）离子的测定限为10^<-10> mol dm^<-3>。此外，10^<-6>-10^<-3> mol dm^<-3>的抑制剂，羧酸和溴离子，也可以动力学测定。理论上，该系统对可能作为反应触发器的物质具有潜在的适用性。分光光度法、停流法和自由基清除剂加成实验的动力学分析数据为反应机理提供了一些信息。例如，配体和配合物的分解反应都是金属催化和非催化的平行反应，但它们通过不同的反应路径推进。这些结果对构建理想的自催化反应体系具有重要意义。

Autocatalytic reactions, in which the reaction product acts as a catalyst, are one of the most effective amplification systems for detection of ultra-trace chemical species. Mathematical model calculation shows that the autocatalytic systems provide the same sigmoidal reactant concentration-time profile at the inflection time for any initial concentration of catalyst, that is, only inflection time correlate with it. We found that it should be great value as a kinetic constant sensitivity detection system and theoretically infinite sensitivity detection methods for catalysts.It was one model for realizing the autocatalytic reaction in laboratory system that the decompmsition of the metal complex causes an amplification of the metal ion having catalytic effect on the own complex. Based on some knowledges about metal complexes got from new analytical method, which is developed in our laboratory and named "kinetic differentiation mode high Performance liquid chromatography (KD-HPLC)" , we have found the decomposition of the inert Co (III) -pyridylazo dye complexes with peroxomonosulfate acts as an excellent indicator reaction system for cobalt (II) ion in phosphate buffer media. The determination limit of cobalt (II) ion was 10^<-10> mol dm^<-3>. Furthermore 10^<-6>-10^<-3> mol dm^<-3> of inhibitors, carboxylic acids and bromide ion, could also be determined kinetically. Theoretically, this system has potential applicability to substances that may act as triggers of the reaction.Kinetic analysis data for spectrophotometry, stopped-flow method, and radical scavenger addition experiment have given some informations on the reaction mechanism. For instance, the decomposition reactions of ligand and complex are both parallel one with metal-catalysis and non-catalysis, however, they advance via different reaction paths. These results are important knowledges to construct an ideal autocatalytic reaction system.