organic_lecture2_10

organic_lecture2_10 - Gas Chromatography Used to identify...

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Gas Chromatography { Used to identify esters in each sample { Used to determine primary components { Stationary phase = column packing z Packed-metal or glass tubing packed with solid support { E.g., glass beads, porous polymer, silica z Capillary-Fused silica coated with liquid substrate { Mobile phase = gas { Absorption occurs through weak intermolecular forces.
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lide 3 T=0 T=10’ T=20’ Injector Injector Detector Detector Most Most Interaction with Stationary Phase Interaction with Stationary Phase Least Least Flow of Mobile Phase Flow of Mobile Phase
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Column Metrics ± Resolution ² Relates to separation of components in a mixture ² Depends on difference in retention times relative to average peak width ± Efficiency ² ² Computed from retention time relative to peak width
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{ factors affecting resolution and efficiency z column material { based on prior experience z column length { resolution increases with length z column packing { small, uniform particle sizes increase efficiency z column diameter { efficiency decreases as column diameter increases z temperature { resolution increases at low temperature { peaks broader and retention times longer at low T © 2005 D.B. King
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{ factors affecting resolution and efficiency z flow rate { low flow rates – diffusion affects resolution
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This note was uploaded on 11/07/2011 for the course CHEM 356 taught by Professor Rowell during the Summer '10 term at Drexel.

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organic_lecture2_10 - Gas Chromatography Used to identify...

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