Dual-mode N4O3 tripodal hemi-salen Schiff base sensor for selective colorimetric detection of Ni2+ and fluorometric sensing of Zn2+: analytical applications across food, environmental, and forensic matrices

Abstract

Tris-(2-aminoethyl) amine and 3,5-Di-tert-butyl-2-hydroxybenzaldehyde are the sources of the tripodal N₄O₃ donor tris-Schiff base hemi-salen molecular probe L, which we have presented here for the sensitive and selective colorimetric detection of Ni²⁺ and turn-on fluorometric detection of Zn²⁺ in aqueous media over a range of other competing cations. The detection limits are 9.4 × 10⁻⁷ M and 4.68 × 10⁻⁷ M, respectively. The FT-IR, ESI-mass, and Job-plot spectrum analyses confirmed a 1 : 1 stoichiometry between the L and Zn²⁺ and L and Ni²⁺ ions. Using Na₂EDTA, the reversible reactivity to the Ni²⁺ and Zn²⁺ ions has been demonstrated. Moreover, L can function across a broad pH range and is helpful for detecting and quantifying Ni²⁺ and Zn²⁺ in food and environmental materials. In a variety of forensic applications, it aids in the creation of latent fingerprints. Molecular docking studies of L have also been reported here as preliminary computational insight into possible biomolecular interactions.