Figure 4.16
A typical elution profile; the separation of saturated esters
by gas-liquid chromatography- methyl formate 2. methyl acetate 3. ethyl formate
- ethyl acetate 5. n-propyl formate 6. iso-propyl acetate
- n-butyl formate 8. sec-butyl acetate 9. iso-butyl acetate
- n-butyl acetate
saturated with sample, the component with the smallest distribution ratio begins to emerge from the
column followed by others in order of increasing distribution ratio but not separated as well as in the
elution method. Displacement development involves the movement of a sample down the column by
introducing a displacing agent which has a larger distribution ratio than any of the sample components.
Again solutes leave the column in order of their distribution ratios, but with much less overlap than in
frontal analysis. Neither of these methods offers any advantages over elution, except in preparative
work where large quantities are to be handled.
4.3.1—
Gas Chromatography
Summary
Principles
Separation of mixtures in microgram quantities by passage of the vaporized sample in a gas stream
through a column containing a stationary liquid or solid phase; components migrate at different rates
due to differences in boiling point, solubility or adsorption.
Apparatus and Instrumentation
Injection port, heated metal, glass or fused quartz column, detector and recorder, regulated gas supply.
Applications
Very widespread use, almost entirely for organic materials; technique is rapid, simple and can cope with
very complex mixtures (100 or more