A novel fluorescence sensor based on a tripodal carboxylic acid for detection and measurement of Cu²⁺ in tomato:...

A tripod organic compound, (4,4',4''-[1,3,5-Triazine-2,4,6-triyltris(oxy)] tribenzoic acid, TCPT), with donor triazine core and multiple fluorophore carboxylic motives, was prepared as an efficient ligand with high emission properties. The TCPT fluorescence emission properties as a chemical sensor were studied (λ_ex = 370 nm) upon the addition of an appropriately diverse set of metal cations. The obtained results revealed the highly selective and efficient role of Cu²⁺ in quenching of TCPT, even with relevant interfering metal ions. The emission of TCPT was independent of the pH. The interaction of the sensor with Cu²⁺ and followed by absorption spectra and linear trend of the Stern-Volmer diagram, suggested a static quenching process. The density functional theory calculations were carried out to explore the identity of the electronic transition levels, HOMO-LUMO, and bandgap energies of TCPT. The linear range 1.00 × 10^-7-1.00 × 10^-6 M was obtained by fluorescence titration of a TCPT solution with Cu²⁺ ions at optimum conditions. The detection limit was calculated as 5.45 × 10^-8 M from the established calibration of titration data. The effect of various ions was studied, and there was no significant interference from the studied metal ions. For the real sample analysis, trace levels of Cu²⁺ ions were successfully determined in the tomato.