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Activating effect of ligands in the catalyzed reactions and its application to the catalytic determination of trace amounts of elements

配体催化反应的活化作用及其在催化测定痕量元素中的应用

基本信息

批准号：
12640589
负责人：
NAKANO Shigenori
金额：
$ 2.3万
依托单位：
Tottori University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

项目摘要

A spectrophotomeric flow-injection method has been developed for the successive determination of copper(II) and iron(III). It is based on the catalytic effect of copper(II) and iron(III) on the hydrogen peroxide oxidation of N,N'-bis(2-hydroxy-3-sulfopropyl)-o-tolidine (HTS) to produce an intensely colored dye (λ_<max> = 670 nm). In the copper(II)-catalyzed reaction, 2,2'-biquinoline, 2,9-dimethyl-4,7-diphenyl^1, 10-phenanthroline disulfonic acid and 2,9-dimethyl-phenanthroine (neocup) were found to be effective activators. On the other hand, 2,2'-bipyridine, 1,10-phenanthroine (phen) and 8-hydroxquinoline-5-sulfonic acid acted as activators in the iron(III)-catalyzed reaction. By introducing the sample solution containing neocup or phen into flow line in the presence of phosphoric acid and triethanolamine as masking agents, copper(II) (1-30 ng ml^<-1>) and iron(III) (2-50 ng ml^<-1>) can be selectively determined with sampling frequency of 20 h^<-1> without any separation procedures.A sensitive flow-injection photometric method has been also proposed for the catalytic determination of vanadium(IV, V), based on the catalytic effect of vanadium(IV, V) on the oxidation of HTS by bromate. The presence of 1,2-dihydroxybenzene-3,5-disulfonate increased the rate of vanadium(IV, V)-catalyzed reaction and significantly enhanced the sensitivity the method. Vanadium(IV) and vanadium(V) in the range 0.01-3.0 ng ml^<-1> were easily determined with sampling rate of about 30 h^<-1>. The limit of detection (S/N = 3) was 0.01 ng ml^<-1> and the relative standard deviations were 1.4 % and 1.6 % for ten determinations of 0.2 ng ml^<-1> vanadium(IV) and vanadium(V), respectively. Interferences from metal ions could be suppressed by the use of ethylenediamine-N,N,N',N'-tetrakis(methylenephosphonic acid) as a masking agent. The proposed method was successfully applied to the determination of vanadium in water samples.

建立了流动注射分光光度法连续测定铜（Ⅱ）和铁（Ⅲ）的新方法。它是基于铜（Ⅱ）和铁（Ⅲ）对过氧化氢氧化N，N ′-二（2-羟基-3-磺丙基）-邻联甲苯胺（HTS）生成一种强着色染料（λ_<max>= 670 nm）的催化作用。在铜（II）催化的反应中，发现2，2 '-联喹啉、2，9-二甲基-4，7-二苯基-1，10-菲咯啉二磺酸和2，9-二甲基-菲咯啉（neocup）是有效的活化剂。另一方面，2，2 '-联吡啶、1，10-菲咯啉（phen）和8-羟基喹啉-5-磺酸在铁（III）催化的反应中充当活化剂。以磷酸和三乙醇胺为掩蔽剂，在流动相中引入含有neocup或phen的样品溶液，在20 h ~ 2的进样频率下，不经分离，可选择性地测定铜（II）（1-30 ng ml<-1>）和铁（III）（2-50 ng ml<-1>）<-1>。1，2-二羟基苯-3，5-二磺酸盐的存在提高了钒（IV，V）催化反应的速率，显著提高了方法的灵敏度。在0.01-3.0 ng/mL范围内的钒（IV）和钒（V）<-1>容易以约30 h/mL的采样速率测定<-1>。方法的检出限（S/N = 3）为0.01 ng/ml<-1>，对0.2 ng/ml的<-1>钒（IV）和钒（V）测定10次，相对标准偏差分别为1.4%和1.6%。用乙二胺-N，N，N ′，N ′-四（亚甲基膦酸）作掩蔽剂，可抑制金属离子的干扰。该方法已成功地应用于水样中钒的测定。