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18 Cards in this Set
- Front
- Back
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What do polar compounds have greater affinity for? |
The polar stationary phase which consists of silica gel |
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More time spent in the mobile phase leads to? |
Decrease retention time |
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Longer retention time is associated with what? |
Greater polarity in column chromatography |
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What is one way to decrease the retention time of the polar compound? |
Change the composition of the mobile phase to a more polar solvent |
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Will increasing the polarity of the mobile phase decrease the retention time of both compounds? |
Yes |
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What mixture is being separated in this lab? |
Methyl orange and methylene blue |
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What is the one major difference between TLC and column chromatography? |
Stationary phase is bound as a thin layer to a solid support such as aluminum |
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Where is the mobile phase introduced in TLC? |
From the bottom (rises via capillary action) |
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What is TLC usually used for? |
To track the progress of a reaction |
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How do you observe the compounds on a TLC plate after elution? |
Place it under a UV active light |
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What are the three main pigments that can be extracted from spinach leaves? |
1. Chlorophylls 2. Pheophytins 3. Carotenoids |
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What is the structural difference between chlorophyll a and b? |
Chlorophyll b has an additional aldehyde group (increased polarity) |
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What is the color of pheophytins? |
Gray (less polar than chlorophylls) |
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What are the two categories of carotenoids? |
1. Carotenes 2. Xanthophylls |
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What is the polarity of carotenes? |
Not very polar which means it is high up on the TLC plate |
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What is the polarity of xanthophylls? |
They are the oxygenated form of carotenes and thus very polar |
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Do carotenes or xanthophylls have a OH group on their structure? |
Xanthophylls |
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What mobile phase mixture was used for the TLC? |
Acetone and hexanes |
