科研之友
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摘要
In this study, a multiplex fluorescence sensor for successive detection of Fe3+, Cu2+ and Hg2+ ions based on "on-off" of fluorescence of a single type of gold nanoclusters (Au NCs) is described. Any of the Fe3+, Cu2+ and Hg2+ ions can cause quenching fluorescence of Au NCs, which established a sensitive sensor for detection of these ions respectively. With the introduction of ethylene diamine tetraacetic acid (EDTA) to the system of Au NCs and metal ions, a restoration of fluorescence may be found with the exception of Hg2+. A highly selective detection of Hg2+ ion is, thus, achieved by masking Fe3+ and Cu2+. On the other hand, the masking of Fe3+ and Cu2+ leads to the enhancement of fluorescence of Au NCs, which in turn provides an approach for successive determination of Fe3+ and Cu2+ based on "on-off" of fluorescence of Au NCs. Moreover, this assay was applied to the successful detection of Fe3+, Cu2+ and Hg2+ in fish, a good linear relationship was found between these metal ions and the degree of quenched fluorescent intensity. The dynamic ranges of Hg2+, Fe3+ and Cu2+ were 1.96 x 10 (10)-1.01 x 10 (9), 1.28 x 10 (7)-1.27 x 10 (6) and 1.2 x 10 (7)-1.2 x 10 M-6 with high sensitivity (the limit of detection of Fe3+ 2.0 x 10 (8) M, Cu2+ 1.9 x 10 M-8 and Hg2+ 2 x 10 (10) M). These results indicate that the assay is suitable for sensitive detection of these metal ions even under the coexistence, which can not only determine all three kinds of metal ions successively but also of detecting any or several kinds of metal ions.
