Aggregation-induced emission-based versatile 3D hierarchical porous nanoprobe for electrochemiluminscence-fluorescence dual-mode detection of Cr(VI)

Abstract

Owing to the built-in cross reference correction function, dual-mode monitoring platform is conducive to perform the highly precise pollution surveillance and traceability analysis in complicated environmental media. Herein, a novel aggregation induced emission (AIE)-based 3D hierarchical porous nanoprobe COP-TPEN2 was successfully synthesized, as to design a electrochemiluminscence (ECL)-fluorescence dual-mode sensing platform for Cr(VI) detection in environmental water samples. Equipped with many -NH groups, COP-TPEN2 can reduce hexavalent chromium Cr(VI) to low-toxicity trivalent chromium Cr(III). Moreover, different valence states of Cr ions were discovered to consume portions of the reactive intermediates of S2O82- (i.e., SO4-), and the electrons during the reduction of COP-TPEN2 were captured due to the strong oxidation property of Cr2O72-, leading to a decrease in the ECL intensity for COP-TPEN2. Moreover, COP-TPEN2 with AIE properties could be applied for Cr(VI) detection in fluorescence channel through the joint action of inner filter effect and static quenching. On account of the different signal generation mechanisms, two independent signals were selectively triggered by Cr(VI), achieving efficient detection of Cr(VI) with LODs of 0.18 nM and 0.29 nM, respectively. This dual-mode sensor was successfully used to determine Cr(VI) in environmental samples with satisfactory results, thereby showing great potential in environmental monitoring.