Stationary Phase
The fixed material in a chromatographic system with which the sample components interact as they pass.
Unit
Dimensionless
In depth
The stationary phase may be a solid adsorbent or a liquid film coated on a support, and its polarity determines the separation mechanism. In normal phase it is polar and non-polar components elute first; in reversed phase the reverse applies.
Examples in the real world
Silica gel in TLC; the C18-bonded silica used in most reversed-phase HPLC columns.