Fig. 6. The black bars represent the fluorescent intensity of sensor Tri-R6G (a) or Tri-Flu (b) and various metal ions (1.0 equiv.) in solution; the red bars represent the fluorescent intensity of sensor Tri-R6G + Hg²⁺ (a) or Tri-Flu + Al³⁺ (b) (1.0 equiv.) in solution.