421-821-chapter-26

421-821-chapter-26 - Introduction to Chromatography...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Introduction to Chromatography Definition Chromatography is a separation technique based on the different interactions of compounds with two phases, a mobile phase and a stationary phase , as the compounds travel through a supporting medium. Components: mobile phase: a solvent that flows through the supporting medium stationary phase: a layer or coating on the supporting medium that interacts with the analytes supporting medium: a solid surface on which the stationary phase is bound or coated
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The analytes interacting most strongly with the stationary phase will take longer to pass through the system than those with weaker interactions. These interactions are usually chemical in nature, but in some cases physical interactions can also be used.
Background image of page 2
Types of Chromatography 1.) The primary division of chromatographic techniques is based on the type of mobile phase used in the system: Type of Chromatography Type of Mobile Phase Gas chromatography (GC) gas Liquid chromatograph (LC) liquid 2.) Further divisions can be made based on the type of stationary phase used in the system: Gas Chromatography Gas Chromatography Name of GC Method Type of Stationary Phase Gas-solid chromatography solid, underivatized support Gas-liquid chromatography liquid-coated support Bonded-phase gas chromatography chemically-derivatized support
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Types of Chromatography Liquid Chromatography Liquid Chromatography Name of LC Method Type of Stationary Phase Adsorption chromatography solid, underivatized support Partition chromatography liquid-coated or derivatized support Ion-exchange chromatography support containing fixed charges Size exclusion chromatography porous support Affinity chromatography support with immobilized ligand
Background image of page 4
3.) Chromatographic techniques may also be classified based on the type of support material used in the system: Packed bed (column) chromatography Open tubular (capillary) chromatography Open bed (planar) chromatography
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Theory of Chromatography 1.) Typical response obtained by chromatography (i.e., a chromatogram): chromatogram - concentration versus elution time W h W Where: t R = retention time t M = void time W b = baseline width of the peak in time units W = half-height width of the peak in time units Inject
Background image of page 6
Note : The separation of solutes in chromatography depends on two factors: (a) a difference in the retention of solutes (i.e., a difference in their time or volume of elution (b) a sufficiently narrow width of the solute peaks (i.e, good efficiency for the separation system) A similar plot can be made in terms of elution volume instead of elution time. If volumes are used, the volume of the mobile phase that it takes to elute a peak off of the column is referred to as the retention volume (V R ) and the amount of mobile phase that it takes to
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 24

421-821-chapter-26 - Introduction to Chromatography...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online