A New Reactive 1,8-Naphthalimide Derivative for Highly Selective and Sensitive Detection of Hg2

Abstract

A 1,8-naphthalimide derivative with a reactive aliphatic hydroxyl was designed and synthesized as a fluorescent probe. Its structure was characterized by IR, ¹H NMR, ¹³C NMR, LC-MS and HPLC. The probe showed high selectivity and sensitivity to Hg²⁺ over other metal ions such as Pb²⁺, Na⁺, K⁺, Cd²⁺, Cr³⁺, Zn²⁺, Cu²⁺, Ni²⁺, Ca²⁺, Fe³⁺, Fe²⁺, Co²⁺, Mn²⁺ and Mg²⁺ in MeCN/H₂O (15/85, v/v). The increase in fluorescence intensity was linearly proportional to the concentration of Hg²⁺ in the range of 18-40 μM with a detection limit of 1.38 × 10^-7 mol/L. The probe could work in a pH span of 4.3-9.0 and respond to Hg²⁺ quickly with strong anti-interference ability. Job's plot suggested a 1:2 complex of the probe and Hg²⁺.

Keywords: Fluorescent probe; Hg2+; Naphthalimide; Phenyl isothiocyanate.