Pressurized high temperature or superheated water is a green extraction solvent used in food, environmental, and traditional medicine studies for the extraction of non-polar and polar analytes including essential oils and spices, agrochemicals, pharmaceuticals, and petrochemicals.
The authors describe the results they've achieved by using water heated to 100–240 ºC as a liquid eluent for reversed-phase HPLC instead of an organic modifier. They point out that this alternative avoids many of the problems – toxicity, flammability, and cost – associated with organic modifiers.