Quinoline-quinoline schiff-base as an effective chromogenic, fluorogenic, and smartphone assisted RGB detection of Pb2+ ion in near aqueous medium

Kathirvel R; Poongodi M; Vetriarasu V; Vivekanandan K E; Selvakumar K; Sami Al Obaid; Arivalagan Pugazhendhi; Geetha Venkatesan

doi:10.1016/j.envres.2024.118530

Quinoline-quinoline schiff-base as an effective chromogenic, fluorogenic, and smartphone assisted RGB detection of Pb²⁺ ion in near aqueous medium

Environ Res. 2024 Feb 22:250:118530. doi: 10.1016/j.envres.2024.118530. Online ahead of print.

Authors

Kathirvel R¹, Poongodi M², Vetriarasu V³, Vivekanandan K E⁴, Selvakumar K⁵, Sami Al Obaid⁶, Arivalagan Pugazhendhi⁷, Geetha Venkatesan⁸

Affiliations

¹ Department of Chemistry, Bharat Ratna Purachi Thalaivar Dr. M.G.R Government Arts and Science College (Affiliated to the Periyar University), Palacode, 636808, Tamil Nadu, India. Electronic address: kathirchem66@gmail.com.
² PG and Research Department of Chemistry, Islamiah College (Autonomous), (Affiliated to the Thiruvalluvar University), Vaniyambadi, 635752, Tamil Nadu, India.
³ Department of Chemistry, Bharat Ratna Purachi Thalaivar Dr. M.G.R Government Arts and Science College (Affiliated to the Periyar University), Palacode, 636808, Tamil Nadu, India.
⁴ Department of Microbiology, Nehru Arts and Science College, Thirumalayampalayam, Coimbatore, 641105, India.
⁵ Department of Physics, Bannari Amman Institute of Technology, Sathyamangalam, Erode, Tamil Nadu, 638401, India.
⁶ Department of Botany and Microbiology, College of Science, King Saud University, PO Box -2455, Riyadh, 11451, Saudi Arabia.
⁷ School of Engineering, Lebanese American University, Byblos, Lebanon; Centre for Herbal Pharmacology and Environmental Sustainability, Chettinad Hospital and Research Institute, Chettinad Academy of Research and Education, Kelambakkam-603103, Tamil Nadu, India.
⁸ Department of Biomaterials, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences (SIMATS), Saveetha University, Chennai, 600077, India. Electronic address: geethavenkatesan31@gmail.com.

PMID: 38387491
DOI: 10.1016/j.envres.2024.118530

Abstract

A novel multimode colorimetric and fluorescent chemosensor was developed using an 8-hydroxy quinoline carbaldehyde Schiff base with a quinoline hydrazide probe (E)-2-((2-(quinolin-2-yl)hydrazineylidene)methyl)quinolin-8-ol (L). NMR (¹H & ¹³C), FTIR, and HR-mass spectral characterization techniques confirmed the probe L structural conformation. As Probe L contacts Pb²⁺ ions, a color change and turn-off emission can be visually detected in EtOH:H₂O (1:1, v/v, pH = 7.21) medium. The probe displays a good emission at 440 nm due to the combined ESIPT and ICT process. The Pb²⁺ ion interacts with the probe and selectively quenches fluorescence by inhibiting ESIPT and >CN- isomerization. As per Job's plot, L-Pb²⁺ complex formation occurred in a 1:1 stoichiometric ratio, with association constant (K_a) and quenching constant (K_sv) estimated at 1.52 × 10⁵ M^-1 and 4.12 × 10⁵ M, respectively. The detection limits of Pb²⁺ by spectrophotometric and spectrofluorometric were 1.99 μM (41 ppb) and 23.4 nM (485 ppt), respectively. Additionally, the test paper kit and RGB tool were used to monitor the color changes of L with Pb²⁺ and the LOD was found to be 5.99 μM (125 ppb). Its recognition mechanism has been verified by ¹H NMR, ESI-mass, and theoretical studies.

Keywords: Chemosensor; Colorimetry; DFT study; Fluorescence; Lead; Smartphone RGB.