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28 Cards in this Set
- Front
- Back
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In the lipid lab, name the four standards you will spot on your TLC plate. Rank in polarity for them.
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1) Cholesterol
2) Triaglycerol 3) Phosphatidylcholine 4) Squalene |
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The silica gel plate is considered ___________. Therefore the _____________ the polarity of the compound, the shorter the distance it will travel on the plate.
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The silica gel plate is considered POLAR. Therefore, the GREATER the polarity of the compound, the shorter it will travel on the plate.
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In the lipid lab, if a compound is polar and you wish to decrease the distance it travels on the gel plate, you should ___________ the polarity of the mobile phase.
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If a compound is polar and you wish to decrease the distance it travels on the silica gel plate, you should DECREASE the polarity of the mobile phase.
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In the lipid lab, which of the following will absorb the least on a silica gel plate. Most?
Ester, charged carboxylic acid, alcohol, hydrocarbon |
Hydrocarbon = least
Charged carboxylic acid = most |
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In general the ____________ a hydrocarbon the more polar the compound, and therewill will travel a relatively ______________ distance on a silica gel
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In general the SHORTER a hydrocarbon, the more polar the compound, and therewill will travel a relatively SHORTER distance on a silica gel.
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What solvent will be used for extraction of lipids from wheat germ?
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2:1 methylene chloride
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What are the components of the polar solvents in the lipid lab?
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Methylene chloride-methanol-water
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What are the components of the non-polar solvent in the lipid lab?
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Light petroleum ether-diethyl ether-acetic acid
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Rank the following from the lowest to highest according to distance traveled on the silica gel plate
Hydrocarbon, ester, alcohol, quarternary nitrogen cpd |
1) quarternary nitrogen cpd = shortest
2) Alcohol 3) Ester 4) hydrocarbon = farthest |
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How high should spots be marked on the thin layer plate? How much is used? Lipid lab
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High enough to be above solvent level
3ul |
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In the lipid lab, will you use pen or pencil to label the spots?
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Pencil, pen will bleed
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In the lipid lab, why is the silica gel plate heated before use?
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To activate and drive off water on plate.
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What is the most polar functional groups in triglycerols?
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Ester
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What is the most polar functional groups in cholesterol?
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hydroxide
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Is squalene a satured or unsaturated hydrocarbon?
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Unsaturated because its made up of isoprene units
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What is the primary difference between plants and animals with regards to fatty acid composition of triglycerides?
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plants = unsaturated. Oil at room temp (liquid)
humans = saturated. Fat at room temp (solid) |
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Why is a nonpolar chromatograph helpful in determining the presence of squalene, cholsterol, and triglercides in your sample?
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Because these are more nonpolar compared to phosphatidylcholine.
They will travel with the nonpolar solvent depending on the degree of polarity More polar means shorter distance traveled! |
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Why are there multiple spots of phosphocholine seem on the polar chromatogram? But there is only one primary spot on the nonpolar chromatograpm?
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Phosphatidylcholine is really polar so it will travel very little if at all. There are serval spots on the chromatograpm because there are several phosphatidylcholines in the mixture
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Rank from most polar to least polar
Phosphatidylcholase, cholsterol, triglycerol, squaline |
1) Phosphatidylcholase (most polar)
2) Cholesterol 3) Triglycerol 4) Squaline (least polar) |
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Why is phosphatidylcholase most polar? Why is squaline least polar? List characteristics
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Phosphatidylcholase is most polar because it has a polar head group with a nonpolar tail with quarternary amino with a + charge.
Cholesterol - Has OH head and nonpolar hydrocarbons Triglycerides - Polar ester group and mostly nonpolar Squaline is least polar because its unsaturated structure makes it polar |
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In your nonpolar chromatogram, which is the stationary phase?
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Silica gel plate.
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In your non-polar chromatogram, list the components of the mobile phase.
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Light petroleum ether-diethyl ether acetic acid
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In your non-polar chromatogram, which is more polar stationary or mobile phase?
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Stationary phase
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In your non-polar chromatogram, which migrates farther?
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Nonpolar
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In the polar chromatogram what is the stationary phase?
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Silica gel plate
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In the polar chromatogram, what are the components of the mobile phase?
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Methyl chloride-methanol-water
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In the polar chromatogram, which is more polar the stationary or mobile phase?
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Stationary.
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In the polar chromatogram did the polar or nonpolar compounds migrate farther?
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Nonpolar.
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