Fig. 3.

(a) Emission spectra of Mito-MPVQ (10 μM) in the presence of various ions in the methanol-water solutions (1:1, v/v, 50mM PBS buffer, pH=7.4). (b) Fluorescence ratio (I_{488 nm}/I_{420 nm}) of Mito-MPVQ upon addition of various metal ions. Experimental conditions: 10 μM Mito-MPVQ, 1 mM Na⁺, K⁺ and Ca²⁺, 10 μM Mg²⁺, Cr³⁺, Ni²⁺, Co²⁺, Cu⁺, Cu²⁺, Fe²⁺, Mn²⁺, Cd²⁺, Zn²⁺, for λ_ex = 330 nm.