NEW APPROACH TO ANALYSIS OF CHEMILUMINESCENCE TRANSIENTS FROM STEP EXPERIMENTS
NEW APPROACH TO ANALYSIS OF CHEMILUMINESCENCE TRANSIENTS FROM STEP EXPERIMENTS
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DOI：
10.1149/1.2134423
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发表时间：
1975-01-01
影响因子：
3.9
通讯作者：
FAULKNER, LR
中科院分区：
文献类型：
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作者：
FAULKNER, LR
研究了从电化学阶跃实验产生的化学发光衰减曲线中提取基本参数的有关问题。重点放在使用早期获得的数据在瞬态，并提出了一种新的方法的基础上曲线拟合。一个通用的ST机制提供了拟合功能，而马夸特算法在实现拟合中起着关键作用。然而，已经开发了周界搜索例程，以消除马夸特算法显示的噪声衰减曲线的不可靠性。整个过程的有效性已被测试的噪声瞬变集，和拟合精度报告的大小和时域的数据库，噪声水平，和在所有发光的S发射的百分比的函数。本文还讨论了绝对发光测量校准误差的影响。研究电化学阶跃实验中的单脉冲发光对理解荧光电子转移过程有重要帮助。这些实验涉及平面工作电极，其最初在最终产生发光的反应物的电化学前体的溶液中保持静止。开始，潜力是。步进到传质受限区以产生第一反应物。例如，红荧烯的阳离子自由基可能是由苯甲腈溶液中的母体烃产生的。该向前步进的宽度tf的范围可以从10秒到10秒。通过将电势切换到质量传递限制区域中的值以产生第二反应物（例如，红荧烯阴离子自由基）来终止。因此，两种反应物在电极附近一起扩散并产生发光，其表现为以非指数形式衰减的脉冲。通常，这个反向步骤的宽度等于tf，并且几乎总是以返回到原始静止电位而结束。费尔德伯格很早就指出了发光瞬变的诊断效用（1，2）。他提出了S-和T-路线的情况下（见下文）的治疗，并表明，人们通常应该获得线性图的形式
A study has been made of problems associated with extracting fundamental parameters from chemiluminescence decay curves generated by electrochemical step experiments. Emphasis is placed on the use of data obtained early in the transient, and a new approach based on curve fitting is advanced. A general ST mechanism provides the fitting function, and the Marquardt algorithm plays the key role in implementing the fit. However, a perimeter search routine has been developed to remove the unreliability that the Marquardt algorithm displays with noisy decay curves. The effectiveness of the entire procedure has been tested on sets of noisy transients, and fitting precision is reported as a function of the size and time domain of the data base, the noise level, and the percentage of S emission in the over-all luminescence. The effects of error in the calibration of absolute luminescence measurements are also discussed.Studying light emission in single pulses from electrochemical step experiments has been an important aid in understanding chemiluminescent electron transfer processes. These experiments involve a planar working electrode which is held initially at rest in a solution of the electrochemical precursors to the reactants that will ultimately yield luminescence. To begin, the potential is. stepped to the mass-transferlimited region for creation of the first reactant. For example, the cation radical of rubrene might be generated from the parent hydrocarbon in a benzonitrile solution. The width, tf, of this forward step might range from 10 sec to 10~ sec. It is terminated by switching the potential to a value in the mass-transfer-limited region for creation of the second reactant (eg, the rubrene anion radical). Thus, the two reactants diffuse together near the electrode and yield luminescence, which appears as a pulse that decays by a nonexponential form. Often this reverse step has a width equal to tf, and it is nearly always ended by a return to the original rest potential Feldberg was early in pointing out the diagnostic utility of the luminescence transient (1, 2). He presented treatments of S-and T-route cases (see below), and showed that one should usually obtain a linear plot of the form