A pH tuning single fluorescent probe based on naphthalene for dual-analytes (Mg²⁺ and Al³⁺) and its application in...

In this study, a naphthalene Schiff-base P which serves as a dual-analyte probe for the quantitative detection of Al³⁺ and Mg²⁺ has been designed. The proposed probe showed an ''off-on'' fluorescent response toward Al³⁺ in ethanol-water solution (1 : 9, v/v, pH 6.3, 20 mM HEPES) over other metal ions and anions, while the detection by the probe could be switched to Mg²⁺ by regulating the pH from 6.3 to 9.4. The sensing mechanisms of P to Al³⁺/Mg²⁺ are attributed to inhibition of the photo-induced electron transfer (PET) process by the formation of 1 : 1 ligand-metal complexes. More importantly, the probe was applied successfully in living cells for the fluorescent cell-imaging of Al³⁺ and Mg²⁺.