靛蓝胭脂红的光谱电化学研究——Ⅱ.靛蓝胭脂红复相电子转移动力学

SPECTROELECTROCHEMICAL INVESTIGATION ON INDIGO CARMINE——Ⅱ.HETEROGENEOUS ELECTRON TRANSFER KINETICS OF INDIGO CARMINE

报道了靛蓝胭脂红在SnO_2透光电极上的复相电子转移动力学参数。由光谱电化学和电化学两种实验方法测定。前一方法为单电位阶跃计时吸收法((SPS/CA)。后一方法为循环伏安法。两种方法的数据处理中均应用了计算机拟合,较之文献中常规的工作曲线法更为简便、正确。两种方法测定的结果十分一致。进一步的研究表明,动力学参数值与靛蓝胭脂红的浓度和溶液pH有关,为靛蓝胭脂红在水溶液中的状态提供了重要信息。

The heterogeneous electron transfer kinetic parameters of Indigo Carmine at tin dioxide optically transparent electrode are reported here in this study.Both spectroelectrochemical and electrochemical techniques were used.In the former case, kinetic parameters were calculated from the normalized absorbance which was measured by absorbance versus time transient curve after serveral overpotential steps.A compu-ter data treatment method instead of the working curve method usually reported inliterature was used in the calculation.In the later case, kinetic parameters were de-termined by measuring the difference of peak potentials ΔE_p of cathodic and anodicsweep as a function of the linear scan rate and were compared with a theoreticalreference curve. The results obtained with both techniques had good coincidence.Further investigation shows that the value of kinetic parameters are dependent onIndigo Carmine concentration and solution pH values. It is considered as an importantinformation for the electroemical reduction mechanism of Indigo Carmine.