CHROMATOGRAPHY

Introducing you to paper chromatography
Where its... spot, elute and treat with N, H, 3.
With H2S you'll pollute it
With spots you'll be saluted
A qualitative analysis with simplicity!

 

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CHROMATOGRAPHY  TUTORIAL
There is a....... VIDEO
Return to the......  Chem 113  SYLLABUS
Return to the......  PRELAB

BASIC PRINCIPLES

Chromatography is a separation technique. It physically separates a mixture into its individual components.

Chromatography is also be useful for identification. Each component moves a characteristic distance and can be identified by color or other property.

The mixture to be separated is put on an immobile matrix such as a solid or grease. This is called the..... stationary phase.

A fluid, liquid or gas, is passed over or through this stationary phase, always only going in one direction. This is called the..... mobile phase.

The components of the mixture are adsorbed on, dissolved in or absorbed by the stationary phase.

The components of the mixture are also dissolved, to varying extents, by the mobile phase.

As the mobile phase passes through the stationary phase, it picks up the components of the mixture by dissolving them. But the stationary phase also competes for the mixture's components by absorbing, adsorbing or dissolving them.

As the chromatogram elutes,

  • the components with strong affinity for the stationary phase and/or little solubility in the mobile phase..... remain near their initial spot.
  • the components very soluble in the mobile phase and/or little or no affinity for the stationary phase..... move away.

and
S E P A R A T I O N
occurs!

Once separated, the presence or absence of a component can be determined.
For a given chromatography system, the relative position of any component remains constant. Furthermore once separated, the identity of any component can be confirmed by it physical and chemical properties.

Visit the PAPER CHROMATOGRAPHY page

RWK