Ce4+-based self-validated portable platform for highly selective and anti-interference visual sensing of phosphate

Abstract

Construction of a convenient and multi-responsive sensor for visual and real-time detecting of phosphate (Pi) is important to monitor the eutrophication pollution or drinking water quality. Herein, we developed a highly selective and anti-interference fluorescent and colorimetric dual-mode sensor for Pi detection. Since only the Ce4+ ion was used as the center with copper nanoclusters (CuNCs) and 3,3′,5,5′-Tetramethylbenzidine (TMB) as the signal carriers, the construction of the sensor was significantly simplified. The dissociated Ce4+ showed ability of triggering the CuNCs aggregation-induced emission (AIE) and oxidase-like enzyme, independently bringing red fluorescence (AIE of CuNCs) and blue color (oxidized TMB) signals. With the presence of Pi, the strong binding between Pi and Ce4+ through P-O-Ce bond quenched both the fluorescent and colorimetric signals. More significantly, the selective and anti-interference ability were effectively improved by self-validation between fluorescent and colorimetric modes. Meanwhile, combining with smartphone, the Pi lowered at 1 μM could be visually detected. Based on the fluorescent and colorimetric outputs could be directly quantified by the naked eye, a paper-based dual-mode visualization platform was constructed. The reliable dual-mode also showed robust analysis of the Pi in environmental water, indicating its great potential as a simple and efficient tool for field monitoring.