Highly sensitive and selective Schiff base chemosensor for Cu2+ and 2,4-D detection: A promising analytical approach.

[Display omitted] • Synthesis of a novel Schiff base-based off–on-off chemosensor SBC-1. • Applied the synthesized chemosensor for the detection of Cu2+ ions. • Applied the SBC-1-Cu2+ complex for the detection of 2,4-D. • Study the performance of SBC-1 and SBC-1-Cu2+ in various water samples. The development of selective and sensitive chemosensors for the recognition of metal ions and pesticides is very important in environmental monitoring, industrial quality control, and public health. In this study, we present a novel Schiff base-based off–on-off chemosensor SBC-1 for the specific and sensitive detection of Cu2+ ions and 2,4-dichlorophenoxyacetic acid (2,4-D). The Schiff base chemosensor forms a complex with Cu2+ (SBC-1-Cu2+), leading to characteristic color changes from bright yellow to light yellow and significant enhancement in fluorescence emission at 584 nm. The resulting complex was further applied for the determination of 2,4-D. The detection limit was calculated to be 0.0028 ppm (0.044 µM) for Cu2+ and 0.0327 ppm (0.147 µM) for 2,4-D. The analytical performance of the Schiff base chemosensor is evaluated in various water samples (pond, lake and tap water) and demonstrating its robustness and reliability for practical use. The percent recovery from these samples was found to be 92.100. ± 0.18 % to 105.333 ± 0.34 % at various levels. Additionally, the chemosensor response mechanisms and binding interactions with heavy metal ions are elucidated through spectroscopic studies. The chemosensor and its complex exhibit remarkable selectivity, providing distinct responses toward Cu2+ and 2,4-D even in the presence of different interfering species. [ABSTRACT FROM AUTHOR]