Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Phay0002 > separation and chromatography > Flashcards

separation and chromatography Flashcards

1
Q

pure substances

A

have fixed melting and boiling points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

purification

A

physical separation of a chemical substance of interest from foreign or contaminating substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

why must drugs be pure in pharmacy

A

impurities could be harmful or cause additional effects
can alter the ability to formulate a drug correctly
can affect stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ways to purify

A

distillation
filtration
centrifugation
recrystallisation
chromatography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what technique can be used for solubility

A

filtration
centrifugation
recrystallisation
liquid liquid separation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Solubility of ionic compounds

A

More soluble in polar solvents than non polar solvents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Solubility of covalent compounds

A

More soluble in non polar solvents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Immiscible

A

Do not mix
Form separated layers or phases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Partially miscible

A

Not too similar but not too different they may mix at determinate proportions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Liquid liquid extractions

A

Two different molecules in one sample may be separated by giving them the choice between different immiscible solvents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Criteria for organic solvent in a liquid liquid extraction

A

Should readily dissolve substance to be extracted
Should not react with the substance to be extracted
Should not react with or be miscible with water
Should ideally have a low bp so it can be easily removed from the product

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Partition

A

The distribution of a solute between two solvents
Compound present in both phases
The solute will distribute itself between the two liquids in accordance with its partition coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Partition coefficient

A

Ratio of the concentration of the solute in one liquid over the concentration in the other
Constant at constant temperature over a limited range of concentrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Partition coefficient equation

A

Concentration in organic/ concentration in aqueous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hydrophobic/ hydrophilic character measured using partition equation

A

P= concentration of drug in octanol/ concentration of drug in water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

High/low P in terms of hydrophobic and hydrophilic

A

Hydrophobic= high P
Hydrophilic = low P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

LogP

A

Measure of hydrophobicity if a drug

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Chromatography

A

Physical method of separation in which the components to be separated are distributed between two phases ( one stationary one in a definite direction)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Distribution coefficient Kx equation

A

Kx= C(stationary) / C (mobile)

20
Q

Analyte

A

Substance to be separated/analysed

21
Q

Eluent

A

Fluid/ solvent entering the column

22
Q

Eluate

A

Fluid/ solvent leaving the column

23
Q

Elution

A

Process of passing liquid through a chromatography column

24
Q

Solid phase extraction

A

Used in sample preparation (pharmaceuticals, blood urine) to remove matrix interferences such as proteins

25
Q

Active substances for solid phase extraction

A

Unretained (matrix interferences adsorbed)
Retained (matrix interferences washed through)

26
Q

Solid phase extraction vs chromatography

A

Column much smaller in SPE
Specialised column in SPE
typically analyses are strongly retained on the SPE column
Impurities washed away in SPE

27
Q

Adsorption chromatography

A

Separation based on difference between the adsorption affinities of the sample analysts for the surface of a solid stationary phase

28
Q

Normal phase

A

More polar compounds more strongly retained
More polar solvents increase elution

29
Q

Reverse phase

A

Less polar compounds more strongly retained
Less polar solvents increase elution

30
Q

Exclusion chromatography

A

Separation based on exclusion effects
Small molecules are retained in the pores of the gel

31
Q

Gel electrophoresis

A

Specialised example of size exclusion chromatography
Separates based on size and charge

32
Q

Ion exchange chromatography

A

Separation based on differences in ion exchange affinities (differences in charges)

33
Q

Thin layer chromatography

A

Analytes move up the plate and are separated according to their Kx

34
Q

Retention factor (Rf)

A

Distance between the middle of the eluding spot and the baseline

35
Q

Column volumes

A

1/ Rf

36
Q

flash column chromotograph

A

gravity so the fastest moving solvent would come out/elute first

37
Q

solvent strength (Eo)

A

more polar solvents elute analytes more rapidly

38
Q

instrumental chromatography

A

high performance liquid chromatography (HPLC)
gas liquid chromatography (GC)

39
Q

HPLC

A

force the analyte through a column of stationary phase by pumping a liquid at high pressure
compounds separated in terms of their ability to interact with the stationary phase

40
Q

advantages of HPLC

A

quantitative precision
variety of columns and detector available
easily automated
no destruction or degradation of sample

41
Q

disadvantages of HLPC

A

creates large volumes of organic solvent waste
drugs analysed must be soluble in the mobile phase
needs maintenance

42
Q

Gas chromatography

A

force the analyte through a column of the stationary phase by the gas at high pressure and high temperatures through a column
high volatility/ low molecular weight elutes first

43
Q

advantages of GC

A

quantitative precision
easily automated
cheap
no mobile parts and low wear and tear
low maintenance
works with extremely low amounts of sample
no solvent waste

44
Q

disadvantages of GC

A

only good for thermally stable and volatile compounds
may require sample derivatisation

45
Q

single point calibration

A

solution with known concentration (standard solution)
find out the relation concentration
use the ratio when injecting unknown concentration of the compound

46
Q

internal standard

A

area under curve of the sample peak and the internal standard peak are compared to give a response factor

Phay0002 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions