A Phenoxyl Radicals-Triggered Colorimetric Analytical Platform for Rapid and In-situ Visual Detection of Amino Pollutants in Water Environments

Amino pollutants ubiquitously discharged from medical, animal husbandry, and aquaculture industries represent a hazardous subgroup of emerging contaminants, yet their rapid and reliable on-site monitoring remains challenging. Herein, we developed a selective analytical system for amino pollutants based on a liquid oxidation recognition probe (LORP) synthesized via a Mn-based advanced oxidation process. The probe selectively captures amino groups through group-selective radical coupling reactions, while crystal violet (CV) enables quantitative and visual readout by converting pollutant concentrations into absorbance signals and color changes. Impressively, this detection system exhibits high selectivity and anti-interference capacity toward complex water matrices and good practicability in tap water, Lake water, fountain water, and aquaculture wastewater with SMX recovery rates of 83.9 to 119.1%. A general synthetic strategy employing structurally diverse phenols was validated, expanding probe accessibility and allowing precise modulation of the LODs and ranges by fine-tuning the phenolic structures. This offers flexible adaptability to different water qualities and detection needs. Overall, this study presents a rapid and practical onsite visual sensing strategy for amino pollutants, featuring phenoxyl radical probes with facile synthesis and operational simplicity.