Chromatography

1
Lecture 15

• Chromatography
• Introduction and Plumbing
• Harris Ch. 23

2
(No Transcript)
3
(No Transcript)
4
(No Transcript)
5
Time tm
Dead time
6
Time tm
Dead time
time
No separation!
7
Mobile phase
Stationary phase
Time for solvent molecule is the same as before
tm
Time for analyte molecule is different tr
Retention time
tm
tr
tr
Adjusted retention time
time
8
Retention factor
Time in stationary phase
Distribution coefficient
Time in mobile phase
If you have many molecules
or
9
Mobile phase
Stationary phase
Time for solvent molecule is the same as before
tm
Time for analyte molecules is different tr(1)
and tr(2)
tm
tr(1)
Selectivity factor Separation factor Relative
retention
tr
tr(2)
time
10
Distribution coefficient
Retention factor k
Separation factor
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
Number of theoretical plates
Plate Number
W 4s
L - length of column
Height of theoretical plate is
H L / N L ? s2 / tr2
Plate Height
15
Zone broadening The van Deemter equation
H - plate height u - flow rate
16
A 0
17
(No Transcript)
18
B
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
van Deemter plot
24
(No Transcript)