Foster Christopher W, de Souza Ana P, Metters Jonathan P, Bertotti Mauro, Banks Craig E
Faculty of Science and Engineering, School of Science and the Environment, Division of Chemistry and Environmental Science, Manchester Metropolitan University, Chester Street, Manchester, M1 5GD, UK.
Instituto de Química - Universidade de São Paulo, 05508-900, São Paulo, SP, Brazil.
Analyst. 2015 Nov 21;140(22):7598-612. doi: 10.1039/c5an01692d.
In this paper in situ bismuth, antimony, tin modified electrodes and combinations thereof are explored towards the model target analytes cadmium(II) and lead(II), chosen since they are the most widely studied, to explore the role of the underlying electrode substrate with respect to boron-doped diamond, glassy carbon, and screen-printed graphite electrodes. It is found that differing electrochemical responses are observed, dependent upon the underlying electrode substrate. The electrochemical response using the available range of metallic modifications is only ever observed when the underlying electrode substrate exhibits relatively slow electron transfer properties; in the case of fast electron transfer properties, no significant advantages are evident. Furthermore these bismuth modified systems which commonly employ a pH 4 acetate buffer, reported to ensure the bismuth(III) stability upon the electrode surface can create create a problem when sensing at low concentrations of heavy metals due to its high background current. It is demonstrated that a simple change of pH can allow the detection of the target analytes (cadmium(II) and lead(II)) at levels below that set by the World Health Organisation (WHO) using bare graphite screen-printed electrodes.
在本文中，研究了原位铋、锑、锡修饰电极及其组合对模型目标分析物镉（II）和铅（II）的作用，选择这两种分析物是因为它们是研究最广泛的，目的是探究基底电极相对于硼掺杂金刚石、玻碳和丝网印刷石墨电极的作用。研究发现，观察到的电化学响应不同，这取决于基底电极。只有当基底电极表现出相对较慢的电子转移特性时，才会观察到使用可用金属修饰范围的电化学响应；在快速电子转移特性的情况下，没有明显的优势。此外，这些通常使用pH 4乙酸盐缓冲液的铋修饰系统，据报道可确保铋（III）在电极表面的稳定性，但在检测低浓度重金属时，由于其高背景电流，会产生问题。结果表明，简单改变pH值可以使用裸石墨丝网印刷电极检测低于世界卫生组织（WHO）设定水平的目标分析物（镉（II）和铅（II））。
