Turn-on fluorescence study of a highly selective acridine-based chemosensor for Zn2+ in aqueous solutions

• Published in: Inorganica Chimica Acta 2020-01, Vol.499, p.119191, Article 119191
• Main Authors: Nunes, Marcelo Carpes, dos Santos Carlos, Fabiane, Fuganti, Otávio, Galindo, Danyellen Dheyniffer Monteiro, De Boni, Leonardo, Abate, Gilberto, Nunes, Fábio Souza
• Format: Article
• Language: English
• Subjects: 4,5-Bis(aminomethyl)acridine; CHEF; Fluorescent chemosensor; Supramolecular chemistry; Zinc(II)
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2019.119191

An acridine-based chemosensor was investigated for quantitative detection of metal ions in aqueous solutions. Fluorescence intensification upon coordination showed selectivity for Zn(II) with no relevant interference, and the sensor was applied in real samples. [Display omitted] •Excellent selectivity for Zn(II) in aqueous solution with no interference.•TDDFT confirmed the CHEF mechanism.•Recovery results were 91.9% for tap water and 99.0% for mineral water.•Robustness was verified based on the variation of several analytical conditions. 4,5-Bis(aminomethyl)acridine (LN) was investigated as a chemosensor for metal ions in aqueous solutions and it is selective for Zn2+, through a linear fluorescence enhancement of 230% in the concentration range of 17.8–600 μmol L−1. Benesi-Hildebrand and Job method formalisms showed the formation of a very stable complex with one of the highest binding constant (2.43 × 1014 L2 mol−2) reported for zinc, and a 2:1 (metal ion/sensor) ratio. DFT and TD-DFT calculations could explain the fluorescence augmentation upon complexation between Zn2+ and LN. Limit of detection and limit of quantification (R2 = 0.9970, least squares method) were found to be 5.36 and 17.8 μmol L−1, respectively, and appropriate robustness was verified based on the variation of several analytical conditions. Practical application testes showed recovery results such as (92 ± 4)% (tap water) and (99 ± 1%) (mineral water), proving to be adequate to quantify Zn2+ in real water samples, showing no effect of interfering ions.