A fluorimetric approach to studying the effects of ionic strength on reaction rates - An undergraduate steady-state fluorescence laboratory experiment
A fluorimetric approach to studying the effects of ionic strength on reaction rates - An undergraduate steady-state fluorescence laboratory experiment
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DOI：
10.1021/ed080p1191
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发表时间：
2003-10-01
影响因子：
3
通讯作者：
Verity, B
中科院分区：
文献类型：
--
作者：
Bigger, SW;Watkins, PJ;Verity, B
本文介绍了一种简单的稳态荧光实验，研究了氯离子和溴离子对奎宁显色荧光的动态猝灭。离子强度足够低的溶液可以用德拜-胡克尔方程来考虑离子活度。该实验演示了反应速度如何取决于介质的离子强度。该实验是应用德拜-胡克尔方程的一个独特的例子，没有使用关于离子活度系数计算的简化假设。实验还表明，观察到的Stern-Volmer速率常数随离子强度的增加而减小的现象可以用定量模型来确定奎宁对Cl-和Br2-荧光猝灭的相对效率。
A simple, steady-state fluorescence experiment is described in which the dynamic quenching of the quinine dication fluorescence by Cl-and Br-is studied. Solutions of sufficiently low ionic strength enable ionic activities to be taken into account by means of the Debye–Hückel equation. The experiment demonstrates how the rate of a reaction depends on the ionic strength of the medium. The experiment represents a unique example of the application of the Debye–Hückel equation without the use of simplifying assumptions regarding the calculation of ionic activity coefficients. The experiment also shows how the observed decrease in the Stern–Volmer rate constant with increasing ionic strength can be quantitatively modeled to determine the relative efficiencies of Cl-and Br-fluorescent quenching of quinine.