【摘要】 水分子与联吡啶钌(Ru(bpy)32+)之间的电化学发光(ECL)反应早已被人们发现,但其增敏Ru(bpy)32+电化学发光信号的能力不强,很难实现分析应用.我们发现四(三羟甲基氨基甲烷)合铜(Ⅱ)(Cu(Tris)42+)可电催化水的氧化反应生成活性中间产物羟基自由基(·OH),·OH能够快速进入二氧化硅基质,有效地增敏联吡啶钌/二氧化硅复合纳米粒子(RuSNPs)的电化学发光,并利用紫外-可见吸收光谱、电化学方法、电化学发光方法等研究了可能的电化学反应机理.基于以上研究,发展了一种以水分子作为共反应试剂,测定铜离子的电化学发光分析新方法.该方法在铜离子浓度为2.0×10-7~1.0×10-4mol/L的范围内,电化学发光强度与铜离子浓度呈现良好的线性,同时该方法具有很好的灵敏度和选择性,检出限(S/N=3)达到1.0×10-7mol/L,且Ca2+、Mg2+、Na+、Fe3+、Pb2+、Cd2+、Co2+、Ni2+、Mn2+等常见离子不干扰测定.使用该法对自来水和黑河水样中铜离子含量进行测定,分别往两个水样中加入2~3倍的铜离子标准溶液,其加标回收率在97.0%~102.5%之间;与原子吸收分光光度法对比,相对误差分别为4.1%和4.7%,说明该方法测定结果具有一定的可靠性.更多还原

【Abstract】 Although many electrogenerated chemiluminescence(ECL) co-reactants, such as tripropylamine(TPA) and oxalic acid, have been applied in Tris(bipyridine)ruthenium(II)/silica nanoparticles(Ru(bpy)32+/silica nanoparticles, Ru S NPs) ECL system, the poor diffusion behavior of these co-reactants in silica matrix as well as its toxic disadvantages limited their further ECL analytical application. Therefore, it was very meaningful to explore a new type of co-reactant in Ru S NPs ECL system for obtaining a good analytical result. In this paper, we found that the electrochemical oxidation reaction of H2 O could be catalyzed by Cu(Tris)42+(Tris(hydroxymethyl)aminomethane, Tris) complexes and produce the intermediate(·OH). The ECL of Ru(bpy)32+-doped Ru S NPs could be induced by ·OH and produce the strong ECL signals. The possible ECL mechanism was investigated by ultraviolet-visible(UV-vis) absorption spectrum, electrochemical methods and ECL methods. It may be that when Cu2+ was added into the Tris-HCl solution, it would combine with the amino of Tris to form Cu(Tris)42+complexes; in the subsequent ECL reaction process, Ru(bpy)32+ inside Ru S NPs near by the surface of electrode was firstly oxidized to Ru(bpy)33+. At the same time, the reduction reaction of Ru(bpy)33+ would catalyze the oxidization of Cu(Tris)42+to generate the Cu(Tris)43+; then, the reduction of Cu(Tris)43+ would catalyze the electrochemical oxidation reaction of H2 O and was accompanied by the generation of O2 and strong reducing agents(·OH). On the one hand, the silica substrate could protect Ru(bpy)32+-doped Ru S NPs from O2 interference, and avoid the quenching effect of Ru(bpy)32+ ECL induced by O2. On the other hand, ·OH can rapidly go through the silica substrate and react with the oxidation state of Ru(bpy)33+ inside of Ru S NPs because it is a kind of neutral group. Based on these findings, we develop a new ECL method for sensitive detection of Cu2+ using H2 O molecular as a co-reacant. Under the optimal conditions, the proposed method achieved a detection limit of 1.0×10-7 mol/L with RSD of less than 5.0%.更多还原