The SDME technique is based on the principle of a distribution of analytes between an organic solvent microdrop and an aqueous phase. The analytes with high partition coefficient can reach high concentrations, once they are transferred by diffusion from a significant volume of sample (1–5 mL) to a microdrop of organic solvent (5–50 μL), thus obtaining a high enrichment factor [28]. The SDME procedure uses a microsyringe with the needle immersed into a water sample containing the analytes.