Fig. 7. (a) Fluorescence emission response of 10 μL GSH-CDs, to various molar equivalents of As³⁺ ions (0 to 30 nM) in 1000 μL of tris–HAc buffer (10 mM, pH 7.4). (b) Stern–Volmer plot with an inset plot shows the linearity for As³⁺ ions (2 to 12 nM).