What is the mechanism of silica gel column fractionation?

[kankyo]

Fractionation using Silica gel column is commonly used to separate the aliphatic and aromatic components of petroleum oil. Hexane is usually used to elute the aliphatic components and dichloromethane for aromatic components? What is the property of hexane and dichlomethane that make them useful to elute the aliphatic and aromatic components respectively as the sample passes through the silica gel column?

[chromatographer1]

silica gel is polar.

hexane is non-polar.

DCM is more polar than hexane.

aliphatics are non-polar.

aromatics are more polar than aliphatics.

Do you see a common thread?

Do you remember the old adage? Like dissolves like?

best wishes,

Rod