CE-UV/LIF Analysis of Organic Fluorescent Dyes for Detection of Nanoplastics in Water for Quality Control

Nanoplastics are a type of plastic that forms because of the degradation of bulk plastics due to several natural factors, and they are everywhere around us. Nanoplastics are a global concern due to their diverse composition. Additionally, detecting and analyzing these particles in water samples is challenging, as they also often bind with organic pollutants. Current water treatment methods are ineffective against nanoplastics, and these plastics can take years to degrade completely. One of the promising methods to detect nanoplastics is using organic fluorescent dyes that can bind to the nanoplastics by interactions with their surfaces. Capillary electrophoresis with UV detection or laser-induced fluorescence are feasible techniques for this, especially laser-induced fluorescence, as it can give much more sensitivity and selectivity for the fluorescent dyes. The research aimed to validate capillary electrophoresis (CE) with UV spectrophotometer/laser-induced fluorescence detection (LIF) for the quantitative analysis of micro/nanoplastics in lake/ground/well/tap water samples using organic fluorescent dyes. CE was used with a blue laser, a photodetector, and a UV detector. A 50%/50% mixture of R6G & DCM (Rhody dye) was used as it showed the most promising results. It was found that the CE-UV/LIF method, especially CE-LIF, has shown potential for analyzing the nanoplastics contents of real-world water samples. Rhody dye mixtures showed good binding to the polystyrene nanoplastics, especially at lower concentrations. However, with the rise of cheminformatics and artificial intelligence-machine learning, fluorescent dye-based chemosensors will be better designed for future applications of CE-UV/LIF.