A portable sensing platform using a novel dipyrrolopyrazinedione-based aza-BODIPY dimer for highly efficient detection of hypochlorite and hydrazine

Abstract

As widely used chemical reagents in different industrial fields, reactive hydrazine (N₂H₄) and hypochlorite (ClO⁻) show significant risks to human health, drink water, and environment. Currently, fluorescence detection of two analytes suffers from slow and minor spectral change, high detection limit and poor selectivity. In this work, by introducing electron deficient 1,4-pyrazine ring enhanced chromophore reaction strategy, a novel dipyrrolopyrazinedione-based aza-BODIPY dimer (PzDP-PPAB) was synthesized for the first time. Interestingly, PzDP-PPAB for dual-responsive detection of N₂H₄ and ClO⁻ has been developed, accompanying with large spectral change (Δλ_ab = 250 nm for N₂H₄ and Δλ_ab = 277 nm for ClO⁻), distinctly dual colorimetric/fluorescent turn-on responses, low detection limits (N₂H₄: 40 nM; ClO⁻: 59 nM) and good selectivity. The sensing mechanism reveals that PzDP-PPAB chromophore as a novel recognition site is selectively disrupted by N₂H₄ and ClO⁻, where two different less conjugated products with diverse outputs were displayed. More importantly, PzDP-PPAB has been effectively utilized for detecting ClO⁻ in both water and vegetables samples with excellent recovery rate. The portable sensing platforms based on silica gel or sponge loaded with PzDP-PPAB provide a visual and convenient method for monitoring N₂H₄ in both solution and gaseous state. This work presents a promising fluorescent probe for monitoring N₂H₄ and ClO⁻ with a novel sensing mechanism capable of efficient detection of two pollutants.