active solid

https://doi.org/10.1351/goldbook.A00109
A porous solid with adsorptive properties by means of which chromatographic separations may be achieved. The separations resulting from this action follow laws different from those deriving from the partitioning action of the liquid phase.
Source:
Orange Book, 2nd ed., p. 98 (https://media.iupac.org/publications/analytical_compendium/)