Fluorescent technique to detect microplastics in a natural matrix using Methylene blue and Nile red

) in ethanol/water. This double stain reduces the background fluorescence of the non-plastic materials, obtaining the best contrast under the green light (ex. 450-490 nm, em. 515 nm). This is the first report of an easy, fast, and non-destructive staining technique to detect MP in natural conditions, that uses Nile red, together with Methylene blue to reduce false positive background staining.