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6 Cards in this Set
- Front
- Back
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The purpose of GC
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To test the purity of a substance and separate the components of a mixture. The relative amounts of the components in a mixture may be determined.
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How does it work?
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It separates a moving gas phase and stationary liquid phase. GC separates the components of a mixture based on their vapor pressures (or boiling points)
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How does gas chromatograph work?
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1. Sample is injected
2. It immediately vaporized in a heated injection chamber and introduced into the carrier gas 3. Vaporized sample is then swept into a column filled with particles coated with a liquid absorbent (contained in a temperature-controlled oven. 4. Sample passes through the column they undergo gas-liquid partitioning processes and the components are separated |
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How does column work?
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It is packed with a liquid or low-melting solid as the stationary phase. The stationary phase has a high boiling point.
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Separation process
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As mixture reaches the column, which is heated in a controlled oven, it begins to equilibrate between liquid and gas phases. It is affected by vapor pressure and volatility (boiling point)
***Vapor pressure and boiling points are INVERSELY Proportional*** |
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Factors determine the rate of a given compound travel
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1. Boiling point
2. Rate of flow of the carrier gas 3. Choice of liquid phase used in the column 4. Length of the column |
