A novel dual-function probe for recognition of Zn²⁺ and Al³⁺ and its application in real samples

A dual-function probe NAHH based on naphthalene was synthesized and characterized. Based on the combination effects derived from the inhabitation of photo-induced electron transfer (PET) and CN isomerization, probe NAHH achieved in the recognition of Zn²⁺ and Al³⁺ both through obvious fluorescence enhancement and color changes detected by naked eye, respectively. Probe NAHH showed high sensitivity with the limit of detection as low as 3.02 × 10^-7 M for Zn²⁺ and 7.55 × 10^-8 M for Al³⁺, indicated the capability of probe NAHH in trace detection for Zn²⁺ and Al³⁺. The binding ratio of NAHH with Zn²⁺ and Al³⁺ were all 1:1 determined by Job plot, and the corresponding association constant was calculated as 8.48 × 10⁴ M^-1 and 4.45 × 10⁵ M^-1, respectively. The mechanism was further confirmed by FT-IR, ¹H NMR titration and ESI-MS analysis. Furthermore, probe NAHH was successfully applied in logic gate construction and the detection of Zn²⁺ and Al³⁺ in Songhua River and test stripe. Fluorescence imaging experiments confirmed that NAHH could be used to monitor Zn²⁺ in plant root.