Faculty of Science and Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama, 350-8585, Japan.
Research Institute of Industrial Technology, Toyo University, 2100 Kujirai, Kawagoe, Saitama, 350-8585, Japan.
J Fluoresc. 2017 Sep;27(5):1929-1935. doi: 10.1007/s10895-017-2131-1. Epub 2017 Jun 21.
The commercially available natural organic dye, carminic acid (CA), an anthraquinone derivative bearing hydroxyl and carboxyl groups as recognition sites was found to be a colorimetric probe for Pb in perfect aqueous solution under neutral conditions with specific selectivity and high sensitivity. Upon addition of Pb, the absorption maximum of CA showed a large red shift, and the resulted color change from red to purple could be easily identified even by the naked eye. The chemical stoichiometric ratio between CA and Pb was determined to be 1:2 through Job plot, Pb titration, and kinetic experiments. Moreover, other environmental relevant metal ions induced no or minimal spectral and color changes. The reversibility of Pb to CA with EDTA even through several cycles was established for practical applications. The results indicated that CA can be a good candidate for simple, convenient and reversible colorimetric detection of Pb in aqueous solution even though it was hard to be applied to determine Pb on the water testing by US EPA.
市售的天然有机染料胭脂红酸（CA）是一种蒽醌衍生物，带有羟基和羧基作为识别位点，在中性条件下的水溶液中被发现是一种用于 Pb 的比色探针，具有特异性和高灵敏度。加入 Pb 后，CA 的吸收最大值发生了很大的红移，并且即使通过肉眼也可以很容易地识别出颜色从红色变为紫色的变化。通过工作曲线、Pb 滴定和动力学实验确定 CA 和 Pb 的化学计量比为 1:2。此外，其他环境相关的金属离子几乎没有或没有引起光谱和颜色的变化。通过 EDTA 甚至几个循环的可逆性建立了 Pb 与 CA 的反应，这为实际应用提供了可能。结果表明，CA 可以作为一种简单、方便和可逆的比色检测水溶液中 Pb 的良好候选物，尽管它很难应用于美国环保署的水质测试中测定 Pb。
