Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

Porath and Flodin introduced dextran-based gels for the size-exclusion variety of this process, and this process's optimal velocity can be found with the Van Deemter equation. The analyte is polar and the column non-polar in the reverse-phase version of the(*) high-performance liquid type of this process. The retention time is calculated as the sample distance divided by the solvent-front distance in the thin-layer and paper versions of this process. For 10 points, identify this technique that passes a mobile phase through a stationary phase to separate constituents of a mixture.

Science