A smartphone-integrated AIE probe for multimodal and real-time detection of peroxynitrite in plasma-activated water

Abstract

Peroxynitrite (ONOO⁻), a key reactive nitrogen species in plasma-activated water (PAW), contributes to its antimicrobial efficacy, rendering it valuable for biomedical, agricultural, and food processing applications. Accurate detection of ONOO⁻ remains challenging due to its short half-life (∼10 ms), low concentration, matrix interference, and the lack of real-time visualization tools. This study introduces CNBT-TPE-BOH, an aggregation-induced emission (AIE) probe for multimodal detection (UV-vis/fluorescence/colorimetric) of ONOO⁻ in PAW. The probe exhibits high sensitivity (the limit of detection (LOD): 0.62 µM), exceptional selectivity, a large Stokes shift (215 nm), and a rapid visual response (within 8 s). Mechanistic studies indicate boronated oxidation by ONOO⁻, followed by nucleophilic cleavage to yield a phenolic intermediate that cyclizes into TPE-NH, resulting in fluorescence quenching and a color change. Integration with smartphone-based colorimetric detection enables on-site ONOO⁻ quantification, achieving recovery rates of 100.79–103.88%. This work addresses the limitations of single-mode detection, providing a practical approach for real-time PAW monitoring.