Poly(aminoamide) Based Fluorescent Microgel: A Functional Platform for Selective Detection and Discrimination of Cu²⁺ and Pb²⁺ Ions via Turn‐off/on Behavior in Water

ABSTRACT Selective detection of more than one metal ion contaminant in water using a single fluorescent probe is challenging. In this work, a one‐pot synthetic approach is presented to prepare fluorescent poly(aminoamide) microgel, which can detect simultaneously and selectively both Cu 2+ and Pb 2+ by fluorescent turn off and turn on at pH 7 and 12 respectively. Further, while testing water containing a mixture of both Cu 2+ and Pb 2+ as contaminants, the microgel can detect the characteristic presence of Cu 2+ at pH 7 and Pb 2+ at pH 12 via their respective turn‐off and on behavior. The mechanistic studies revealed that the dynamic quenching defines the fluorescent turn‐off behavior of the microgel in the presence of Cu 2+ . On the other hand, aggregation‐induced emission (AIE) is primarily responsible for the fluorescent turn‐on of the microgel in the presence of Pb 2+ . Additionally, applicability of microgels in real life industrial applications are checked by detecting the presence of both analytes in waste water sample collected from a local sewage treatment plant (STP water).