Department of Chemistry, Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, Japan.
Department of Chemistry, Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, Japan.
Ultrason Sonochem. 2020 May;63:104947. doi: 10.1016/j.ultsonch.2019.104947. Epub 2019 Dec 26.
The electrochemiluminescence (ECL) of tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)) in the presence of lidocaine was investigated under ultrasound (US) irradiation. The sonoelectrochemical experiments are conducted by indirect irradiation of ultrasound with a piezoelectric transducer operating at 430 kHz. In a supporting electrolyte at pH 11, the Ru(bpy)/lidocaine system gave weak ECL peaks around +1.2 V and +1.45 V, respectively. The ECL signal at +1.2 V was attributed to redox reactions of the oxidative intermediates of Ru(bpy) and lidocaine, while the signal at +1.45 V was assumed to be caused by an advanced oxidation process due to the generation of hydroxyl radicals (OH) at the electrode surface. In this study, the potential modulation approach is employed in the study of ECL process upon US irradiations because it can suppress the noise components from sonoluminescence effectly and improve the resolution of ECL-potential profiles. It is found ECL signals were greatly enhanced upon US irradiation at the output power of 30 W, however, the relative intensity of ECL signal at +1.2 V was larger than that obtained with a rotating disk electrode even though the mass transport effect is equilvalent. The experiment results suggest that the chemical effect (i.e., generation of OH) by 430 kHz US becomes remarkable in the electrochemical process. Detailed ECL reaction routes under US are proposed in this study.
在超声（US）辐照下研究了三（2,2'-联吡啶）钌（II）（Ru（bpy））在利多卡因存在下的电化学发光（ECL）。通过使用在 430 kHz 下工作的压电换能器间接辐照超声进行声电化学实验。在 pH 为 11 的支持电解质中，Ru（bpy）/利多卡因体系在+1.2 V 和+1.45 V 左右分别给出了微弱的 ECL 峰。+1.2 V 的 ECL 信号归因于 Ru（bpy）和利多卡因的氧化中间体的氧化还原反应，而+1.45 V 的信号则假定是由于在电极表面生成羟基自由基（OH）而导致的高级氧化过程。在这项研究中，由于可以有效地抑制声致发光效应的噪声分量并提高 ECL 电位曲线的分辨率，因此在 US 辐照下采用电位调制方法研究 ECL 过程。结果发现，在 30 W 的输出功率下 US 辐照大大增强了 ECL 信号，但是，即使传质效应相等，+1.2 V 的 ECL 信号的相对强度也比使用旋转圆盘电极获得的更大。实验结果表明，430 kHz US 的化学效应（即 OH 的生成）在电化学过程中变得很明显。在这项研究中提出了 US 下的详细 ECL 反应途径。
