suppressor column - in ion chromatography, refers to the column placed after the ion-exchange column. Its purpose is to remove or suppress the ionization of buffer ions so that sample ions can be observed in a weakly conducting background with a conductivity detector.

surface area - in an adsorbent, refers to the total area of the solid surface as determined by an accepted measurement technique such as the BET method using nitrogen adsorption. The surface area of a typical porous adsorbent such as silica gel can vary from 100 to 600 m2/g.

See surface area.

surface chemistry - chemical and physico-chemical properties of the adsorbent surface. Interactions of the analyte with the adsorbent surface depends on the type of the ligands chemically attached to the surface.

See surface chemistry.

surface coverage - usually refers to the mass of bonded ligands per unit area of an adsorbent. Often expressed in mole/m2 of surface. Sometimes the %C is given as an indicator of surface coverage.

See bonding density.

swelling - process in which resins and gels increase their volume because of their solvent environment. Solvent enters ion-exchange resin to dilute ions; in gels, solvent penetrates pores. If swelling occurs in packed columns, blockage or increased back pressure can occur. In addition, column efficiency can be affected.