Development of highly sensitive method for the determination of trace

自催化反应以反应产物为催化剂，是检测超痕量化学物种的最有效的放大系统之一。数学模型计算表明，对于任何初始浓度的催化剂，自催化体系在拐点时刻提供了相同的S形反应物浓度-时间分布，即只有拐点时刻与之相关。我们发现作为一种动力学常数灵敏度检测系统和理论上无限灵敏的催化剂检测方法具有很大的应用价值。金属络合物的分解导致对自身络合物具有催化作用的金属离子的放大是实现实验室体系自催化反应的一种模型。根据本实验室发展的一种新的分析方法“动力学差示模式高效液相色谱”对金属络合物的一些认识，发现在磷酸盐缓冲介质中，惰性钴(III)-吡啶偶氮染料络合物与硫代过氧单硫酸盐的分解是钴(II)离子的良好指示反应体系。钴(II)离子的检出限为10^~(-10)~(-10)~(-3)。此外，还可用动力学方法测定缓蚀剂、羧酸和溴离子的摩尔分数为10^~(-6)~(-6)~(-3)~(-3)。从理论上讲，该体系对可能引发反应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添加实验的动力学分析数据为反应机理提供了一些信息。例如，配体和络合物的分解反应都是金属催化和非催化平行进行的反应，但它们通过不同的反应途径进行。这些结果为构建理想的自催化反应体系提供了重要的知识。

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.