Reversed-phase chromatography

Uses alkyl chains covalently bonded to stationary phase particles to produce a hydrophobic stationary phase, which has a stronger affinity for less hydrophobic or polar compounds. The use of hydrophobic stationary phase is basically the opposite of normal phase chromatography, because the polarities of the mobile phase and stationary phase have been reversed, so it is called reversed phase chromatography [43]. Therefore, the hydrophobic molecules in the polar mobile phase tend to be adsorbed to the hydrophobic stationary phase, and the hydrophilic molecules in the mobile phase will pass through the chromatographic column and be eluted first, using organic (non-polar) solvents to reduce the polarity of the mobile phase.