Lin Huei-Chi, Chou Yi-Hsin, Yang Jyisy
Department of Chemistry, National Chung-Hsing University, Taichung 402, Taiwan.
Anal Chim Acta. 2008 Mar 17;611(1):89-96. doi: 10.1016/j.aca.2008.01.069. Epub 2008 Feb 7.
An evanescent wave infrared chemical sensor for the sensitive and selective detection of copper ions in aqueous solutions is described. Because copper ions have no vibrational features, a band-shifting technique was utilized to produce the analytical signal. To enhance the sensitivity of the detection process, a three-step procedure was employed to prepare acidified tris(2-aminoethyl)amine (ATAA) phase on an evanescent wave sensing element. This sensing phase has a chemical structure similar to that of ethylenediamine tetraacetic acid (EDTA), a common chelating agent for metal ions. After formation of complex with copper ions, the shifts in the absorption bands of the ATAA phase were used for quantitation. An additional four sensing phases having chemical structures related to that of EDTA were synthesized to compare their performances for detection of copper ions. The synthetic sensing phases are highly stable in water and insensitive to changes in solutions at pH greater than 4. ATAA was the most sensitive of the phases tested, probably because of the accessibility and flexibility of the functional groups in the ATAA phase. To explore these systems in greater detail and to optimize detection, the effects of parameters such as the buffer concentration, the pH of the sample solution, and the matrix effect on response time and linearity of detection were examined. The analytical signals for copper ions were similar - and highly selective - when the pH of the solution was between 5 and 6.5. For a detection time of 5min, these signals were linear for concentrations up to 200microM with a detection limit ca. 3microM.
描述了一种用于灵敏且选择性检测水溶液中铜离子的倏逝波红外化学传感器。由于铜离子没有振动特征，因此采用了带移技术来产生分析信号。为了提高检测过程的灵敏度，采用三步程序在倏逝波传感元件上制备酸化三（2-氨基乙基）胺（ATAA）相。该传感相的化学结构与乙二胺四乙酸（EDTA，一种常见的金属离子螯合剂）相似。与铜离子形成络合物后，利用ATAA相吸收带的位移进行定量分析。合成了另外四种化学结构与EDTA相关的传感相，以比较它们检测铜离子的性能。合成的传感相在水中高度稳定，对pH大于4的溶液变化不敏感。ATAA是测试相中最灵敏的，这可能是由于ATAA相中官能团的可及性和灵活性。为了更详细地研究这些体系并优化检测，研究了缓冲液浓度、样品溶液pH值和基质效应等参数对响应时间和检测线性的影响。当溶液pH值在5至6.5之间时，铜离子的分析信号相似且具有高度选择性。对于5分钟的检测时间，这些信号在浓度高达200微摩尔时呈线性，检测限约为3微摩尔。
