A kit for separating a sample comprising one or more biological analytes of interest using a multi-phase system comprising: a) two or more phase components selected from the group consisting of a polymer, a surfactant, and combinations thereof; b) optionally a tag molecule capable of binding the one or more biological analytes of interest; and c) instructions for: (i) combining the two or more phase-separated solutions with a common solvent to create a multi-phase system; (ii) optionally, combining the biological analyte of interest and tag molecule, and (iii) separating the biological analyte of interest from the sample.