Topics - Reversed Phase

Reversed Phase Reversed phases are dispersive in character and the term, reversed phase has a curious history. The first chromatography columns (Tswett and later Martin) used calcium carbonate and silica as the stationary phase (which were polar) and a hydrocarbon or chlorinated hydrocarbon as the mobile phase (which were dispersive). Thus, the solutes were predominantly retained by polar interactions and predominantly eluted by dispersive interactions. Martin wanted to separate some dispersive substances (long chained fatty acid esters) and so wanted dispersive interactions to dominate in the stationary phase. He, thus, reversed the original system making the stationary phase a high molecular weight hydrocarbon (liquid paraffin) coated on a support and used water or water-alcohol mixtures as the mobile phase. As a result the dispersive hydrocarbon phase was called the reversed phase and, as a consequence, the concept persisted and all dispersive substances have been called reversed phases. Typical reversed phases (dispersive phases) are hydrocarbons, chlorinated hydrocarbons, naphthenes and C8, C16 and C24 bonded phases etc. The use of this term is becoming less common with time