| Abstract
| - The unique characteristic of subcritical water is its widelytunable physical properties. For example, the polarity(measured by dielectric constant) of water is significantlydecreased by raising water temperature. At temperaturesof 200−250 °C (under moderate pressure to keep waterin the liquid state), the polarity of pure water is similar tothat of pure methanol or acetonitrile at ambient conditions. Therefore, pure subcritical water may be able toserve as the mobile phase for reversed-phase separations.To investigate the retention behavior in subcritical waterseparation, the retention factors of BTEX (benzene, toluene, ethylbenzene, and m-xylene), phenol, aniline, andtheir derivatives have been determined using subcriticalwater, methanol/water, and acetonitrile/water systems.Subcritical water separations were also performed usingalumina, silica-bonded C18, and poly(styrene−divinylbenzene) columns to study the influence of the stationaryphase on analyte retention under subcritical water conditions.
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