In recent years, the use of elevated temperatures in liquid chromatography has become more familiar, although many people still fear to increase the temperature because of unwanted side effects. In most laboratories, separations are usually performed at room temperature. In this setting, elevated-temperature liquid chromatography would mean the temperature ranges from 40 °C to 60 °C, whereas high-temperature liquid chromatography extends from 60 °C to 200 °C. The lower temperature limit of 60 °C is defined by the fact that some solvents that are used in liquid chromatography start to boil above that temperature, 1 while the upper temperature limit is dictated by the column stability. Most stationary phases are not stable if the temperature is increased above 150 °C, although it would be very easy to heat a column to a much higher temperature. In fact, only a few stationary phases can be used with an acceptable lifetime between 150 °C and 200 °C. 2 In the literature, many different terms have been used. These are:• Subcritical water chromatography 3-16 • Elevated-temperature liquid chromatography 17-39 • Superheated water chromatography 40-59 • Hot eluent liquid chromatography 60 Fast Liquid Chromatography-Mass Spectrometry Methods in Food and Environmental Analysis Downloaded from www.worldscientific.com by CHINESE UNIVERSITY OF HONG KONG on 02/08/15. For personal use only.