Synthesis, characterization and applications of schiff base chemosensor for determination of Cu2+ ions

A novel thiazole-based Schiffbase chemosensor SB1 with N- and O- donor atoms was synthesized and characterized by different techniques (UV–vis, 13C NMR, 1H NMR, and FT-IR analysis). The chemosensor SB1 was used for the determination of Cu2+ ions in various samples. The significant spectral changes in absorption spectra of chemosensor SB1 at 220 and 416 nm and the color change from light yellow to yellowish-brown indicate high selectivity and sensitivity towards Cu2+ ions as compared to other cations (Na+, K+, Ag+, Zn2+, Ni2+, Pb2+, Mn2+, Mg2+, Co2+, Cd2+, Sn2+, Hg2+, Cr3+, Fe3+, and Al3+). The sensing mechanism of SB1 was investigated through various techniques such as FT-IR, UV–vis and 1H NMR titration experiment and further confirmed by DFT computational studies. The 2:1 binding mode between SB1 and Cu2+ ions was confirmed by Job‘s plot using UV–vis spectrophotometry. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.015 and 0.0471 µg mL−1, respectively. The percent recovery of Cu2+ from various environmental samples was found to be 95.00–103.33% at various levels. These obtained results demonstrate that chemosensor SB1 is a cost-effective, facile, selective, sensitive, and colorimetric sensing platform to detect trace amounts of Cu2+ ions in variousenvironmental and agricultural samples.