Staining Strategies for the Fluorescence Detection of Nano-Microplastics

The nano- and microplastics (NMP) are ubiquitous in the environment. Indeed, they are present in the air, water, soils, many living organisms, and different food and beverage products. Detection, identification, and/or quantification were performed using various analytical techniques. Most NMP identification is achieved primarily through Raman and infrared microscopy, while its identification and quantification are mainly performed using thermal gas chromatography coupled with mass spectrometry. Due to the inherent characteristics of analytical fluorescence techniques, it is one of the most widely used methods for analyzing NMP. To do that, the NMP were usually stained with various fluorescent organic dyes. Fluorescent NMP staining is primarily performed with Nile Red, the principal organic dye used. This NMP fluorescence analysis was performed using steady-state fluorescence microscopy. Fluorescence nanoparticles, such as carbon dots or conjugated polymer nanoparticles, are emerging as a potential alternative to organic dyes for the fluorescence-based visual detection of NMP. The fluorescence-based detection of NMP focuses on staining strategies and the characteristics of staining fluorescence detection using organic dyes and fluorescent nanoparticles, which were reviewed. A critical review of the various staining fluorescence strategies already employed, along with the fluorescence characteristics of organic dyes and fluorescent nanoparticles, will be conducted.