This paper presents an innovative methodology for the detection of primary and secondary microplastics and nanoplastics (MNPs) in diverse aquatic environments using the fluorescent dye Nile Red-n-heptane (NR-H). The escalating pollution from plastic waste and its subsequent fragmentation into MNPs has become a critical environmental issue, infiltrating ecosystems and posing significant ecological and health risks. Traditional methods for detecting MNPs often involve lengthy and costly sample preparation and extraction processes. Our approach seeks to address these limitations by enabling rapid, in-situ detection of MNPs directly in water samples.

Our method leverages the hydrophobic properties of NR-H, which selectively binds to plastic particles, allowing for their detection under fluorescent microscopy. This study demonstrates the effectiveness of the NR-H staining technique across various types of water, including wastewater, borehole water, seawater, and synthetic seawater. The methodology was rigorously evaluated using scanning electron microscopy (SEM), dynamic light scattering (DLS), and optical microscopy to validate the presence and characteristics of MNPs.

Key findings include the successful detection of...

Our study further explored the quantification capabilities of the NR-H technique, addressing potential limitations in sensitivity and specificity. The use of a submersible fluorescence probe was incorporated into the protocol, facilitating real-time, direct measurements in situ. This development is particularly advantageous for environmental monitoring, offering a practical tool for mapping plastic pollution in various aquatic settings.

The research also highlighted the adaptability and robustness of the NR-H method in different environmental conditions. Tests conducted in saline littoral waters and other challenging environments confirmed the method's reliability and precision. These validations underscore the method's potential for broader application in environmental science and pollution management.

One of the notable advantages of this method is its contribution to ...

Further research is proposed to refine the quantification aspects of the NR-H method and to expand its applicability to a wider range of polymer types and environmental conditions. The development of standardized protocols and the potential integration of advanced spectroscopic techniques, such as fluorescence lifetime imaging (FLIM) and hyperspectral imaging, are recommended to enhance the specificity and accuracy of MNP detection.

In conclusion, this paper presents a significant advancement in the field of environmental microplastic detection. The NR-H based method offers a practical, efficient, and reliable tool for the rapid identification and quantification of MNPs in diverse aquatic environments. By addressing the critical need for effective monitoring and management of plastic pollution, this research contributes valuable insights and methodologies that can support global efforts to protect and preserve aquatic ecosystems...