Main content area

Identification and quantification of microplastics using Nile Red staining

Shim, Won Joon, Song, Young Kyoung, Hong, Sang Hee, Jang, Mi
Marine pollution bulletin 2016 v.113 no.1-2 pp. 469-476
Fourier transform infrared spectroscopy, ethylene-vinyl acetate, fluorescence, fluorescent dyes, hexane, plastics, poly(vinyl chloride), polyamides, polyesters, polyethylene, polypropylenes, polystyrenes, polyurethanes, sand, staining, water pollution, weathering
We investigated the applicability of Nile Red (NR), a fluorescent dye, for microplastic analysis, and determined the optimal staining conditions. Five mg/L NR solution in n-hexane effectively stained plastics, and they were easily recognized in green fluorescence. The NR staining method was successfully applied to micro-sized polyethylene, polypropylene, polystyrene, polycarbonate, polyurethane, and poly(ethylene-vinyl acetate), except for polyvinylchloride, polyamide and polyester. The recovery rate of polyethylene (100–300μm) spiked to pretreated natural sand was 98% in the NR stating method, which was not significantly (p<0.05) different with FT-IR identification. The NR staining method was suitable for discriminating fragmented polypropylene particles from large numbers of sand particles in laboratory weathering test samples. The method is straightforward and quick for identifying and quantifying polymer particles in the laboratory controlled samples. Further studies, however, are necessary to investigate the application of NR staining to field samples with organic remnants.