Fig. 2. Fluorescence spectra of TCF-GSH (5 μM) with addition of GSH (0–500 μM) and 15 min wait between additions in PBS buffer solution, 20% v/v DMSO, pH 8.00 at 25 °C. λ_ex = 560 ± 15 nm. Orange dashed lines indicate fluorescence decrease at high GSH concentrations.