fig20

Figure 20. (A) Proposed mechanism of R6G-NA with Hg²⁺; (B) Fluorescence titration spectra analysis of R6G-NA in the presence of different concentrations of Hg²⁺ Inset: the ratio of fluorescence intensity at 550 and 520 nm as a function of Hg²⁺ concentrations; (C) UV-vis absorption spectra of R6G-NA (M) with different contents of Hg²⁺; (D) An image exhibiting both the color shift (left) and fluorescence transformation (right) of R6G-NA prior to and following its interaction with Hg^2+[140]. Copyright 2015, Elsevier B.V. UV-vis: Ultraviolet-visible.