Optical sensors and arrays: development strategies and applications for environmental monitoring

The development strategies of novel sensing materials and analytical systems remains challenging nowadays. Optical sensors, or optodes, transform changes of optical phenomena, as the result of the interaction between the analyte and the receptor part, and detect the intensity of photon radiation that arrives at a sensor. Among chemical sensors with different transduction principles the optical transduction is often preferred, due to the fast response time, simplicity of preparation, and easy signal acquisition procedure. The construction of the most modern optical sensors requires neither wire connection with the detector, no sophisticated and energy-consuming hardware, and thus enabling wearable and wireless sensors development. The analytical signal of optode can be registered with consumer optoelectronic devices such as digital scanners, digital cameras (alone-staying or embedded in commonly used PCs, tablets and smartphones), or visually, without any power supply in a ‘naked-eye’, and especially useful in situations of rapid qualitative analysis and alarm situations. In the present work the strategies of novel optical sensors development and their application both in single and array configuration for liquid samples analysis for environmental monitoring proposes will be discussed. The applications of fluorometric and colorimetric all-solid-state optical sensors and sensory arrays recently developed or under investigation in our laboratories for monitoring of pollutants such as heavy metal ions, per- and polyfluoroalkyl substances - PFAS, cyanobacterial toxins, pharmaceuticals, micro- and nano-plastics and others will be illustrated.