Figure 4.

Selectivity of Hg²⁺ and Au³⁺ using NGODs as probes using PL spectroscopy (a) PL intensity vs wavelength at λ_ex = 344 nm for different metal ions at 250 μM concentration (except Au³⁺ at 300 μM) and (b) corresponding normalized graph at λ_em = 441 nm (F₀ = NGOD PL intensity in deionized water and F₁ = PL intensity with the metal ions). The selectivity was additionally checked with Ag⁺, Mn²⁺, Mg²⁺, and Zn²⁺ (ref to Figure S3).