Rational design of a water-soluble chemodosimeter for highly selective cyanide detection

A low–molecular–weight polyethylene glycol (PEG)-modified aniline–indandione conjugate ( AI) chemodosimeter was synthesized and compared with its dimethylaniline–indandione precursor. Although the synthesized PEGylated chemodosimeter is highly water soluble, it maintains a high fluorescence quantum yield in the neat film state. When exposed to cyanide in aqueous and solid states, AI exhibits significant changes in color and fluorescence owing to nucleophilic addition, effectively inhibiting the intramolecular charge transfer process. The limit of detection of cyanide by AI is 2.3 × 10−7 M, aligning with other established cyanide-selective sensors and significantly lower than the World Health Organization's recommended limit of 1.9 × 10−6 M. We developed simple and affordable paper-based test strips embedding AI , facilitating fast, quantitative, and on-site cyanide detection, visible through color changes and fluorescence. This study demonstrates a practical molecular design strategy for developing water-soluble chemodosimeters tailored for selective cyanide detection.