Tomcik P, Bustin D
Department of Analytical Chemistry, Slovak University of Technology, Bratislava, Slovak Republic.
Fresenius J Anal Chem. 2001 Oct;371(4):562-4. doi: 10.1007/s002160101010.
An interdigitated microelectrode array (IDA) sensor has been applied to the determination of iodide in mineral water. It is based on reversible charge transfer in the redox system I2/2I- at a platinum microelectrode. The analytical signal from the IDA system was obtained by use of a bipotentiostat in dual mode. One segment of the IDA (generator) was polarized to the limiting current for oxidation of iodide to iodine in 0.1 mol L(-1) HClO4. The second segment (collector) was fixed at a potential value corresponding to the limiting current of iodine reduction. The geometrical arrangement of the IDA enables this transfer with high efficiency. Because the diffusion layer of both segments overlaps the iodide produced on the collector, the iodide diffuses back to the generator where it is reoxidized. Therefore, redox cycling will enhance the voltammetric signal of the IDA. The signal obtained with a vertically separated IDA was 20 times higher than that in the single mode. Because multiplication of the signal reduces the detection and determination limits, direct voltammetric determination of iodide in mineral water is possible.
一种叉指式微电极阵列（IDA）传感器已被应用于矿泉水中碘化物的测定。它基于铂微电极上I₂/2I⁻氧化还原体系中的可逆电荷转移。IDA系统的分析信号通过使用双恒电位仪以双模式获得。IDA的一段（发生器）被极化至极限电流，以使碘化物在0.1 mol L⁻¹ HClO₄中氧化为碘。第二段（收集器）固定在对应于碘还原极限电流的电位值。IDA的几何排列使得这种转移高效进行。由于两段的扩散层与收集器上产生的碘化物重叠，碘化物扩散回发生器并在那里被重新氧化。因此，氧化还原循环将增强IDA的伏安信号。垂直分离的IDA获得的信号比单模式下高20倍。由于信号倍增降低了检测和测定限，因此可以直接伏安法测定矿泉水中的碘化物。
