TLC Flashcards

1
Q

What is the MP?

A

a volatile liquid, which is drawn up by capillary action

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2
Q

What are common MP?

A

chloroform, toluene, acetic acid, methanol and small amount of water

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3
Q

What are the types of detectors used?

A

UV light, iodine chamber, chemical stain

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4
Q

What are common SP?

A

silica gel, alumina, polyamides, cellulose

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5
Q

What are the advantages of TLC?

A

costs, and a good technique for purity check

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6
Q

What are the categories of commercial plates?

A

Thick layer silica gel - (200-500 um) dp ~ 20um N~2000

Thin layer silica gel -(100 um) dp~20um N~4000

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7
Q

What is RF?

A

x/y range of {0 - 0.99}

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8
Q

More polar compounds equal _________

A

smaller RF values

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9
Q

Less polar compounds equals _________

A

larger RF values

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10
Q

What is Rs?

A

2(Z2 - Z1)/[w1 + w2]

Rs > 1 much better separation

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11
Q

What is the relationship between polarity and the MP?

A

more polar solvents displace substrates from stationary phase more easily than less polar solvents

more polar the MP the faster the substrate travels

can increase polarity to point where there is no separation

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12
Q

What must be considered when prediction elution order?

A

polarity of each compound in the mixture
polarity of the stationary phase
polarity of the mobile phase

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13
Q

What are some other advantages to TLC?

A

simultaneous analysis and separation

solute movement is always observable

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14
Q

What is the order of polarity for solvents (least to most)?

A
hexane
carbon tetrachloride
toluene
chloroform
diethyl ether
ethyl acetate
methanol
acetic acid
water
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15
Q

What is the order of polarity for substrates (least to most)?

A
alkanes
alkenes
ethers
alkyl halides
aromatics
aldehydes and ketones
alcohols
amines
organic acids
salts
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