In this work, we introduce a new sample preparation method for the extraction and preconcentration of selenium in dietary supplement tablets and mineral water. The bio-coacervation extraction technique is based on the use of a three-part system consisting of an ionic liquid, a biosurfactant and water. The advantage of this method is that the three components are non-toxic, green and ecofriendly. Parameters affecting the extraction efficiency, such as the amount of biosurfactant, the volumes of water and ionic liquid, pH, ionic strength, time extraction, temperature and the extraction method, were optimized. The calibration graph was linear, in the range of 0.55–40 μg L−1. The detection limit for selenium after quantitative analysis was 0.183 μg L−1 and the enrichment factor 190. The relative standard deviation for six replicate measurements was 4.6 %.
