Field-deployable colorimetric chemosensor for on-site selective and sensitive detection of volatile primary amine vapors

The realization of sustainable, cost-effective, and field-deployable chemosensors for on-site and real-time detection of pollutants remains a challenge for current research. This paper reports on the development of a low-cost, field-deployable colorimetric chemosensor for the selective detection of n-butylamine (BA) and primary amine vapors. The chemosensor consists of paper-based films simply prepared by the dip-coating technique, from solutions of a vapochromic Zn(salen)-type complex. The sensor films are characterized by optical uniformity and repeatability. The sensor exhibits high stability over time, while maintaining its sensitivity, which is preserved even under varying environmental conditions, such as different temperatures and relative humidity. The sensor is highly responsive, with fast response times. Both under static exposure conditions and in simulated leakage experiments, the sensor films enable the selective colorimetric detection of BA vapors over a wide concentration range, from units to hundreds of ppm, including the PEL-C (5 ppm) and IDHL (300 ppm) values, via a simple and straightforward readout approach using a smartphone-assisted color recognition app and refined and validated RGB color method by reflectance spectral analysis. Overall, this sustainable colorimetric chemosensor meets the requirements of operational reliability, portability, fast response time and simple readout, making it suitable for on-site and real-time detection, as well as a wearable sensor, of volatile primary amine vapors for human health and environmental safety.