Fig. 4. The fluorescence spectra of Tri-R6G (a) and Tri-Flu (c) (10 μM) with the increasing concentration of Hg²⁺ and Al³⁺ ions (0–1.3 μM) in DMSO/H₂O (7/3, v/v) and ethanol, respectively; the linear fit between Tri-R6G (b) with Hg²⁺ ions and Tri-Flu (d) with Al³⁺ ions.