Figure 4.

Emission spectra of acrylic/QDs nanospheres acting as: (a) single K⁺ sensors after addition of KHCO₃ solutions. (b) Single Cl^- sensors after addition of NaCl solutions. (c) K⁺/Cl₂ multi-ion sensors after addition of KCl solutions. Concentrations: 0mM(black), 2 mM(red), 5mM(green), 10mM (blue), 20 mM (cyan), 50 mM (pink) and 200 mM (yellow). Fluorescent signals were recorded between 450 and 750 nm (λ_ex = 400 nm) with a spectrofluorimeter (Cary Eclipse, Varian) in a 96-well microplate. For all samples the pH was fixed at 7.0 by using phosphate buffer. [101] - Reproduced by permission of The Royal Society of Chemistry.