Highly Sensitive Multiresponsive Chemosensor for Selective Detection of Hg2+ in Natural Water and Different Monitoring Environments

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• 作者：Dayu Wu ; Wei Huang ; Zhihua Lin ; Chunying Duan ; Cheng He ; Shuo Wu ; Dehui Wang
• 刊名：Inorganic Chemistry
• 出版年：2008
• 出版时间：August 18, 2008
• 年：2008
• 卷：47
• 期：16
• 页码：7190-7201
• 全文大小：713K
• 年卷期：v.47,no.16(August 18, 2008)
• ISSN：1520-510X

文摘

A new chemosensor RF1 that combines a ferrocene unit and a rhodamine block via the linkage of a carbohydrazone binding unit was designed and prepared for the highly selective detection of Hg²⁺ in natural water. This chemosensor displays great brightness and fluorescence enhancement following Hg²⁺ coordination within the limit of detection for Hg²⁺ at 1 parts per billion (ppb). The fluorescence intensities are nearly proportional to the amount of Hg²⁺ at the ppb level. It is capable of distinguishing between the safe and the toxic levels of inorganic mercury in drinking water. Hg²⁺-binding also arouses the absorption of the rhodamine moiety in RF1 significantly with the chromogenic detection limit for Hg²⁺ at 50 ppb. The conventional UV-vis spectroscopic method thus has the potential to provide the critical information about the mercury hazard assessment for industrial wastewater discharging. The obvious and characteristic color change of the titration solution from colorless to pink upon the addition of Hg²⁺ demonstrates that RF1 can be used for “naked-eye” detection of Hg²⁺ in water. The Hg²⁺ complexation also causes a significant shift of the redox potential about the ferrocene/ferrocenium couple. The electrochemical responses provide the possibility to quantitative analysis of Hg²⁺ at the parts per million (ppm) level. Preliminary investigations in natural water samples including seawater and freshwater indicate that RF1 offers a direct and immediate Hg²⁺ detection in complex media, pointing out its potential utility in environment monitoring and assessment. The responses of RF1 are Hg²⁺ specific, and the chemosensor exhibits high selectivity toward Hg²⁺ over other Group 12 metals, alkali, alkaline earth metals, and most of the divalent first-row transition metals. The RF1-Hg²⁺ complex is successfully isolated and the Hg²⁺-binding is reversible. The crystal structure and spectral properties of its congener RF2 that contains one ferrocene group and two rhodamine 6G moieties were also investigated for a comparison.