Welchrom® C8 is similar to C18 bonded phase in adsorptivity, mainly depending on non-polar carbon bond interactions. However, due to the alkyl chain of C8 is shorter than that of C18 chain, the retention of non-polar compounds is weaker than that of C18, which is helpful to elution of non-polar samples with too strong adsorbability. C8 column can extract both fat-soluble and water-soluble vitamins from plasma and it is also used in the desalination of biological macromolecular samples. Welchrom® C8 is a commonly used non-polar adsorbent with hydrophobicity less than that of C18 and the retention of non-polar compounds weaker than that of C18, which is conducive to desorption after adsorption of non-polar overstrong samples. For alkaline analytes, the use of C8 adsorbent can increase extraction efficiency and recovery rate.