A robust cyanide sensor for multiphase detection: Enabling practical on-site applications

A new colorimetric and fluorimetric probe PBT, for the efficient recognition of cyanide ion was synthesized and characterized; the sensing properties were analyzed and used for various real-time applications. The probe consists of a D-π-A conception with a donor unit of phenothiazine and an acceptor unit of benzothiazole to make a molecule for the ease of charge transfer transition. The mechanism of recognition is confirmed by ¹H NMR and HRMS spectral analysis. The jobs method also confirms the 1:1 stoichiometric ratio between the PBT and CN^-. The detection limit obtained to be 1.73 μM and 0.14 nM by the absorption and fluorescence methods is less than the allowable limit set by the World Health Organization. The synthesized probe demonstrates the real-time applications in cyanide sensing, like test strips and detection using smartphones based on RGB. The development of probe-embedded capsules is significantly efficient for cyanide detection. The probe-coated test strips developed in this study offer a sensitive, quick, and practical technique for real-time detection of cyanide gas, validating effectiveness across solid, solution, and gaseous phases. These cost-effective and adaptable techniques do away with the necessity for costly lab equipment, allowing for accurate and reasonably priced on-site evaluations.