Column Chromatography (Liquid-Solid) Flashcards
What is the usual stationary phase (in general)?
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What is the ‘sample’ and what do we do with it (in general)?
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What is the Mobile Phase? What is it’s other name? What does it do (in general)?
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Why does separation of the components occur?
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What is the difference in meanings between “Adsorbed” and Dissolved”?
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What are the 4 separation factors?
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Which 2 Adsorbents are the most popular? What is 1 special thing about the first one?
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What is the ‘Activity’ of an adsorbent? Why are some more active than others? What is the result (in regards to the bands) of a more active one than a less active one?
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Why is it important to keep containers tightly closed and to minimize their exposure to atmospheric moisture?
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Which 2 kinds of adsorbents are good for most purposes?
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How much adsorbent should be used? What does it depend on? What is the correlation between Polarity Difference and Column Length?
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What happens if Particles are too small? If Particles are too LARGE?
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How is Particle Size of an adsorbent indicated? What is a Mesh #? What is the correlation between Mesh # vs. Particle Size? What is a typical mesh # for Silica Gel vs. Alumina?
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What is the Role of the Mobile Phase?
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Why is it best to start with a low polarity Mobile Phase?
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Why are several solvents used in sequence, starting with the weaker eluants?
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How exactly should you change (throughout the experiment) your solvents used? What is the Rule of Thumb in regards to when to change your solvent?
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What does the set-up look like?
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How slow should the flow rate be? What exact #s can be used for most purposes? Do difficult separation require slower or faster flow rates?
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What are the 3 Keys to packing a column properly?
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Why must the adsorbent be kept covered with the solvent at all times?
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