Catalytic effect on silver electrodeposition of gold deposited on carbon electrodes
Catalytic effect on silver electrodeposition of gold deposited on carbon electrodes
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DOI：
10.1002/elan.200302973
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发表时间：
2004-10-01
期刊：
影响因子：
3
通讯作者：
Costa-García, A
中科院分区：
文献类型：
--
作者：
de la Escosura-Muñiz, A;González-García, MB;Costa-García, A
这项工作开发了一种基于银电催化沉积的新方法，旨在量化沉积在碳糊电极（CPE）和玻碳电极（GCE）上的金。仅当金预先在电极表面上以足够的电位沉积一段固定的时间时，才会在 -0.13 V 下电沉积银（在 1.0 M NH3 中制备）。当 CPE 用作工作电极时，金的充分氧化是必要的。该氧化在 0.1 M NaOH 和 0.1 M H2SO4 中以氧化电位进行。当 GCE 用作工作电极时，不需要氧化步骤。此外，还包括 KCN 中的清洁步骤，用于去除电极表面的金。为了获得分析信号的再现性，必须对电极表面进行适当的预处理；该电极预处理取决于用作工作电极的电极类型。通过这种新颖的方法，可以实现短金沉积时间（CPE 10 分钟，GCE 5 分钟）的低检测限（5.0 x 10(-10) M）。最后，可以使用银电催化沉积和 GCE 作为工作电极来定量金硫苹果酸钠。从5.0×10^-10M到1.0×10^-8M，银阳极剥离峰与金硫苹果酸盐浓度之间存在良好的线性关系。
A new methodology, based on silver electrocatalytic deposition and designed to quantify gold deposited onto carbon paste electrode (CPE) and glassy carbon electrode (GCE), has been developed in this work. Silver (prepared in 1.0 M NH3) electrodeposition at -0.13 V occurs only when gold is previously deposited at an adequate potential on the electrode surface for a fixed period of time. When a CPE is used as working electrode, an adequate oxidation of gold is necessary. This oxidation is carried out in both 0.1 M NaOH and 0.1 M H2SO4 at oxidation potentials. When a GCE is used as working electrode, the oxidation steps are not necessary. Moreover, a cleaning step in KCN, which removes gold from electrode surface, is included. To obtain reproducibility in the analytical signal, the surface of the electrodes must be suitably pretreated; this electrodic pretreatment depends on the kind of electrode used as working electrode. Low detection limits (5.0 x 10(-10) M) for short gold deposition times (10 min for CPE and 5 min for GCE) were achieved with this novel methodology. Finally, sodium aurothiomalate can be quantified using silver electrocatalytic deposition and GCE as working electrode. Good linear relationship between silver anodic stripping peak and aurothiomalate concentration was found from 5.0 x 10(-10) M to 1.0 x 10(-8) M.