Reversed Phase SPE Cartridge
The principle of the reversed-phase SPE cartridge is to use a non-polar adsorbent (carbohydrate or polymer) on the stationary phase to separate the organic solute from the polar phase (water).
The interaction force between non-polar substances is van der Waals attraction, and the affinity of the adsorbent to the solute mainly depends on its hydrophobicity. Commonly used organic solvents: acetonitrile, ethyl acetate, methanol, or a mixture of dichloromethane and ethyl acetate as eluents.