A thiazole-based colorimetric and photoluminescent chemosensors for As³⁺ ions detection: Density functional theory,...

A Schiff-base Ethyl (E)-2-(3-((2-carbamothioylhydrazono)methyl)-4-hydroxyphenyl)-4-methylthiazole-5-carboxylate (TZTS) dual functional colorimetric and photoluminescent chemosensor which includes thiazole and thiosemicarbazide has been synthesized to detect arsenic (As³⁺) ions selectively in DMSO: H₂O (7:3, v/v) solvent system. The molecular structure of the probe was characterized via FT-IR, ¹H, and ¹³C NMR & HRMS analysis. Interestingly, the probe exhibits a remarkable and specific colorimetric and photoluminescence response to As³⁺ ions when exposed to various metal cations. The absorption spectral changes of TZTS were observed upon the addition of As³⁺ ions, with a naked eye detectable color change from colorless to yellow color. Additionally, the chemosensor (TZTS) exhibited a new absorption band at 412 nm and emission enhancements in photoluminescence at 528 nm after adding As³⁺ ions. The limit of detection (LOD) for As³⁺ ions was calculated to be 16.5 and 7.19 × 10^-9 M by the UV-visible and photoluminescent titration methods, respectively. The underlying mechanism and experimental observations have been comprehensively elucidated through techniques such as Job's plot, Benesi-Hildebrand studies, and density functional theory (DFT) calculations. For practical application, the efficient determination of As³⁺ ions were accomplished using a spike and recovery approach applied to real water samples. In addition, the developed probe was successfully employed in test strip applications, allowing for the naked-eye detection of arsenic ions. Moreover, fluorescence imaging experiments of As³⁺ ions in the breast cancer cell line (MCF-7) demonstrated their practical applications in biological systems. Consequently, these findings highlight the significant potential of the TZTS sensor for detecting As³⁺ ions in environmental analysis systems.