The invention relates to a method and device for obtaining micro and nanometric particles in a controlled, reproducible manner. The aforementioned particles have a spherical shape and a very narrow, uniform size distribution. More specifically, the invention relates to a novel method of forming emulsions and to the application thereof in micro and nanoencapsulation techniques involving the extraction/evaporation of the solvent. In particular, the invention relates to the encapsulation of the fluorescent compounds and the subsequent application thereof.