Page 13 - Illustrated Pocket Dictionary of Chromatography

6 ADSORPTION ISOTHERM

adsorption isotherm A plot constructed from the equilibrium
concentration of an analyte in the mobile phase per mass of sorbent.
The shape of the isotherm and the relative concentration of the
analyte with respect to the sorbent are factors that determine the
elution profile. See Langmuir and Freundlich isotherms.

adsorption site A specific area on a stationary phase where the
analyte (or any other component of the mobile phase) can interact
with the stationary phase. For example, on alumina supports, the
adsorption sites are basic, neutral, and/or acidic electron-acceptor
aluminol groups. On an octadecyl bonded-phase silica stationary
phase the adsorption sites are the residual silanol groups (technically
the octadecyl groups are considered to be involved in a partition
process). Note that the type and concentration of these sites in a given