Chromatography Flashcards

(27 cards)

1
Q

What is the basic principle of chromatography?

A

The partitioning of analyses between a stationary phase and a mobile phase

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2
Q

What happens to compounds with partition coefficient favouring the mobile phase?

A

They migrate faster than compounds that favour the stationary phase

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3
Q

What is a eluent?

A

Mobile phase

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4
Q

What is elution?

A

The motion of solute and solvent through the stationary phase

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5
Q

What is effluent?

A

The mobile phase (and solute) collected at thread of the chromatography

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6
Q

What is resolution?

A

The degree of separation

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7
Q

What did the mobile phase move through the stationary phase via?

A

Capillary action

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8
Q

What is the distance travelled by the analyte determined by?

A

It’s relative affinity for the stationary versus the mobile phase

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9
Q

What is the stationary phase?

A

A plate (glass,plastic,aluminium) coated with adsorbent SiO2

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10
Q

What percentage of weight volume of solvent is the sample dissolved in?

A

1-2% w/v

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11
Q

What is the most common stationary phase?

A

Silica gel

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12
Q

Name two other polar stationary phases?

A

Cellulose and alumina

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13
Q

What do more polar compound absorb more onto?

A

The stationary phase and less time in the mobile phase

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14
Q

What is the Rf usually quoted as?

A

Rfx100 value

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15
Q

What is the intensity of a spot on a TLC plate related logarithmically to?

A

The concentration of the analyte producing it

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16
Q

As polarity increases what happens to the Rf value for each compound in the mixture?

A

The Rf value increases

17
Q

How is the sample visualised after separation?

A

Use if UV light is a non-destructive method

Need to use silica gel plate impregenated with fluorescent material

18
Q

What wavelength does the sample illuminate at?

19
Q

Name a general purpose developing reagent?

20
Q

What does iodine produce?

A

Brown spots with many organic compounds

21
Q

What is potassium permanganate used for?

A

Detection of sugars and sugar- like molecules

22
Q

What is Ninhydrin solution used for?

A

Detection of primary and tertiary amines.
Used in the identification of aminoglycoside antibiotics such as gentamycin.
Also used in conjunction with Dragendorff reagent

23
Q

What % is ethanol/sulfuric acid used in producing fluorescent spots from corticosteroids?

24
Q

What are applications of TLC?

A

Limit tests- example such as impurities in hydrocortisone acetate

25
What are strengths of TLC?
Flexible: mobile and stationary phase, spray reagents. Robust and cheap Entire chromatogram can be seen Used for many drugs impurities Can be run in batches and can be automated
26
What are limitations of TLC?
Limited number of theoretical plates available for separation Limited sensitivity Unsuitable for volatile compounds Requires a degree of operator skill
27
What is chromatography?
Is one of the best methods for separating and measuring the components of a mixture