GEC and GFC Flashcards
1
Q
Large molecules are retained _______ than small molecules.
A
less
2
Q
In SEC, the retention volume is related to the _______
A
void volume
3
Q
Large molecules:
A
Vr = V0,
Kav = 0
4
Q
Intermediate size molecules:
A
Vr > V0
Kav 0-1
5
Q
Small molecules:
A
Vr ~ Vt
Kav ~ 1
6
Q
What is the exclusion limit?
A
defines MW beyond which no retention occurs
7
Q
Beyond the permeation limit_________
A
all molecules elute in one band since they can all freely penetrate the pores
8
Q
Advantages of SEC
A
short, well-defined retention times
narrow bands, good sensitivity
no sample loss
9
Q
Disadvantages of SEC
A
limited number of bands accommodated since short time scale
not applicable to similar size molecules (isomers)
10
Q
What is GFC?
A
aqueous solvent
hydrophilic packings
11
Q
What is GPC?
A
nonpolar organic solvents
hydrophobic packings
