High-temperature liquid chromatography of steroids on a bonded hybrid column.

A hybrid stationary phase, XTerra MS C18, has been evaluated for the high-temperature reversed-phase liquid chromatography of selected hydrophobic steroids. The effects on the retention and efficiency at temperatures up to 130 degrees C and eluent compositions from methanol-water mixtures to superheated water were studied. The thermodynamic data of the separations were determined. It was shown that increasing the temperature enabled the percentage of methanol to be reduced. High mobile-phase flow rates could be used, but for these non-polar analytes, the retention times with superheated water as the eluent were still high.