How To Freely Change the Polarity of the Stationary Phase in a Liquid Chromatographic Column

The concept of changing the polarity of the stationary phase in a liquid chromatographic column is developed. Three phases are presented which all contain a sulfur atom in the sulfide form. On oxidation of the sulfur atom with iodosobenzene in the packed column, a sulfoxide group is formed which is considerably more polar. This change can be performed in infinitesimally small steps and convert the phase from essentially unpolar to quite polar. The polarity change is reversible. The separation of several classes of compounds on these new phases in both the oxidized and the reduced forms is compared with that on traditional phases.