Bindone-based polymer for colorimetric detection of volatile amines†

Abstract

Effective detection and monitoring of volatile amines are crucial for protecting human health and the environment, particularly in areas such as disease diagnosis and food spoilage detection. Traditional gas sensors, including electrochemical, semiconductor, and photochemical types, often suffer from limited selectivity, sensitivity and require complex and expensive synthesis and detection equipment. Colorimetric sensors, which are easily interpreted through visible colour changes, have recently gained attention for their simplicity and real-time detection capabilities. In this study, we present a chemosensing system based on the bindone motif, both as a small molecule (Bin) and embedded in a polymer backbone (PBin), for the effective colorimetric detection of volatile amines. Our system exhibits high selectivity and sensitivity, with detection limits as low as 0.04 ppm for Bin and 1.57 ppm for PBin. The colour change, driven by amine-induced tautomerisation, was confirmed through UV-Vis spectroscopy, NMR spectroscopy, and TD-DFT calculations. pH dependent studies reveal the importance of basicity on the mechanism and selectivity. By incorporating the bindone moiety into the polymer backbone, its thermal stability was significantly enhanced. The versatility of the sensor was demonstrated in solution, and paper-based film formats, with successful application in detecting amines released during fish spoilage. This work highlights the potential of the bindone-based chemosensor as a cost-effective, portable, and efficient tool for monitoring food freshness and other applications requiring the detection of volatile amines.