Deionized water was used as the solvent for titration experiment.
The titrations were carried out in 10-mm quartz cuvettes at
room temperature. Probe 1 was dissolved in DMF (spectroscopic
grade) to afford a concentration of 10 mM stock solution, and then
diluted with PBS buffer (pH = 7.4, 10 mM). Anions (as their Na+ salt,
10 mM and 100 mM) in deionized water were added to the diluted
probe solution and used for the sensing behavior experiment. The
excitation wavelength was 400 nm, and the PMT voltage was 700V.
The excitation and emission slit width were 5 nm and 5 nm, respectively.