Fluorescence-based detection: A review of current and emerging techniques to unveil micro/ nanoplastics in environmental samples

Plastic pollution represents a global environmental issue with relevant associated risks for ecosystem and human health. Fluorescence-based detection techniques allowed rapid tracking and identification of micro/nanoplastics (MNPs) in numerous studies by combining pre-treatment procedures, specific staining protocols, and advanced analytical instruments. However, despite an increasing scientific attention, the detection of plastic debris in the submicron and nano size range is still challenging when targeting environmental complex samples. In particular, the suitable approaches are not consistently harmonized and generally case/system-specific, with detrimental consequences on data reproducibility, accuracy, and reliability. This review is intended to provide state-of-the-art information on the existing and promising fluorescence-based approaches to assess the occurrence of MNPs in environmental samples of different origin. More specifically, we identified and discussed the most used fluorescent dyes, staining protocols, and analytical instruments for the fluorescence-based detection of MNPs. Advantages and disadvantages of the applied methodological approaches were critically presented, by highlighting their potentialities and challenges in view of future needs to improve the current scientific knowledge on spread and fate of MNPs in the environment. Overall, fluorescence-based techniques are offering promising results and unique analytical opportunities for the detection and quantification of MNPs in the environment.