A novel spectrophotometric method for the determination of Cr(III) ions in aqueous media using a synthesized Schiff base derivative

A novel and efficient spectrophotometric technique has been developed for the selective detection of Cr³⁺ ions in aqueous media utilizing a synthesized Schiff base derivative, <i>N</i>-(5-(1 H-benzo[d]imidazol-2-yl)-4-(2-‎oxoindolin-3-‎ylideneamino)pyrimidin-2-yl)-4-‎methylbenzene sulfonamide‎‎ (IBSB). The molecular structure of the synthesized compound was thoroughly characterized using ¹H and ¹³C NMR, along with FT-IR spectroscopy. The chemosensor exhibited remarkable sensitivity and ‎‎selectivity towards Cr³⁺ in aqueous media, maintaining its analytical ‎performances even in the ‎presence of various competing metal cations and ‎anions. The binding between Cr³⁺ and IBSB occurs with a 1:1 stoichiometric ratio, inducing a distinct pale green color change observable to the naked eye. ‎IBSB exhibits a rapid and precise response to Cr³⁺ within a linear range of ‎‎5 to 95 µM ‎and a detection limit of 1.2 µM. The sensor’s practical ‎application was validated through the ‎successful detection of Cr³⁺ ions in ‎natural and simulated water samples. The Cr(III)-IBSB ‎complex exhibited a ‎binding constant of 2.66 × 10³ M⁻¹, indicating a strong interaction. This spectrophotometric method presents a simple, cost-effective, and rapid alternative to traditional techniques for Cr³⁺ determination, with promising potential for environmental, industrial, and possibly biological monitoring applications.