A dual-emission fluorescence coordination polymer for simultaneous quantification of Al3+ and Pb2+ in their mixtures

Abstract

Owing to the high toxicity of metal ions to the environment and public health, as well as metal contaminants often containing multiple metal ions, it is imperative to detect them simultaneously. In this study, we investigated the fluorescence sensing properties of the coordination polymer [Gd(adip)_1/2(dht)_1/2(NMP)₂] (1), which exhibited dual emission bands. The emission peaks at 409 and 427 nm were highly sensitive to quenching by Al³⁺ and Pb²⁺ ions. By contrast, only the emission peak at 540 nm exhibited fluorescence turn-on response to Al³⁺ ions, accompanied by a blue shift of 20 nm in the range of 540 to 520 nm. Compound 1 exhibited different response signals to Al³⁺ and Pb²⁺, without any interference between their respective signals. This study demonstrates the potential of 1 for simultaneous detection of Al³⁺ and Pb²⁺, and their mixtures in complex soil samples. In addition, a comprehensive study was conducted to investigate the sensing mechanism of this complex system.