Exam 3

Wall-coated open tubular column

liquid stationary phase on inside wall of column

Porous-layer open tubular column

Solid stationary particles on inside wall of column

Packed column

column filled with solid stationary phase particles

Molecular sieves

In/organic materials with cavities into which small particles enter and are partially retained

Adsorption Chromatography

A solid stationary phase + liquid or gaseous mobile phase
Solute is adsorbed onto the surface of the solid particles
The more strongly a solute is adsorbed, the slower it travels through the column

Partition Chromatography

Liquid stationary phase is bonded to a solid surface
Solute equilibrates between the stationary liquid and the gaseous mobile phase
(Ex: gas chromatography; liquid polymer bonded to inside surface of an open tube of fused silica)

Ion-exchange Chromatography

Anions or cations are covalently attached to stationary solid phase, usually a resin
Solute ions of opposite charge are attracted
Liquid mobile phase

Size exclusion chromatography

Separates molecules by size
Larger pass through more quickly
No attractive interaction between stationary phase and solute
Liquid/gaseous mobile phase passes through a porous gel
Pores small enough to exclude large ones, not small ones; So large ones stream through while small molecules do and are sheltered from mobile phase

What does Van Deemter tell you???

How the column and linear velocity affect plate height