Figure 6.

(a) Photoluminescence spectra of MPA-coated Mn-ZnSe/ZnS QDs in PBS buffer (pH = 7.4) in the presence of different amounts of Hg²⁺ ions (0–20 nM). The excitation wavelength was 400 nm. (b) Calibration curve of the QD fluorescence at 588 nm vs. [Hg²⁺] (0–1.5 nM). The inset: a linear relationship between I/I₀ at 588 nm vs. [Hg²⁺] (0–1.5 nM), R² = 0.981.