This document provides an introduction and overview of chromatography. It discusses how chromatography separates a complex mixture into individual components based on interactions between a mobile and stationary phase. Different types of chromatography are described based on variations in the stationary and mobile phases used, including gas chromatography (GC), liquid chromatography (LC), high performance liquid chromatography (HPLC), thin layer chromatography (TLC), supercritical fluid chromatography (SFC), ion chromatography (IC), size exclusion, capillary zone electrophoresis (CZE), and affinity chromatography. Key terms used to describe chromatographic separations such as retention time, capacity factor, selectivity factor, resolution, number of theoretical plates, and plate height are also defined.

1. Introduction to Chromatography
Separate a complex mixture into individual
Components based on interactions between a
Mobile phase and a stationary phase
Amp = Asp
K = [A]sp / [A]mp
Chromatographic system: column plus detector
Chromatogram: Plot of Detector Response
as a function of elution time

3. GC
LC
HPLC
TLC
SFC
IC
Size Exclusion
CZE
Affinity
Chromatography: Different Types
http://www.youtube.com/watch?v=08YWhLTjlfo
http://www.youtube.com/watch?v=kz_egMtdnL4

4. Sp: solid
Mp: liq or gas
Equil btwn ads. state and liq-gas
Adsorption

5. Partition
Sp: liq on solid
Mp: liq or gas
Equil btwn liq. state and liq-gas

6. Ion Exchange
Sp: ion exch. resin
Mp: liq
Electrostatic attractions

7. Sp: porous gel
Mp: liq
Permeation into the gel
Molecular Exclusion

8. Affinity
Sp: solid with immobilized molec
Mp: liq
Specific interactions

9. SFC
Sp: solid
Mp: SC fluid
Partition btwn fluid and adsorbent

10. Describe the separation
tR = retention time
tm = dead time
tR
’
= adjusted retention time

11. k’
= capacity factor
Describes migration rate of a solute
Larger k’
, longer the solute is retained
Good values: 1-5
k’
= (tR - tm) / tm
k’
= K (Vs/Vm)
Describe the separation

12. α = selectivity factor
How well the column separates 2 species
Larger the number, the greater the sepn btwn the two
Always greater than 1
α = KB / KA
α = k’
B / k’
A
α = (tR,B – tm) / (tR,A – tm)
Describe the separation

13. Efficiency of a Separation
Two Factors
1- elution times btwn peaks
2- how broad the peaks are

14. Qualitative
Eddy Diffusion
Longitudinal Diffusion
Rate of Mass Transfer

15. Eddy Diffusion
Multiple paths
Independent of flow rate
Depends on particle diameter…

16. Longitudinal Diffusion
Concentration gradients
Greater flow  less spreading
Depends on Diffusion Coeff….

17. Equilibration
Greater flow rate  more spreading
Depends on Diff. Coeff, stationary phase…
Rate of Mass Transfer

18. Quantitative Description: N,H,R
Examine Peaks
R = ∆tR / Wavg
R = (tR,2 – tR,1) / Wavg
R > 1.5 is good

19. Quantitative Description: N,H,R
Number of Theoretical Plates (N)
N = L/H N = 16tR
2
/ Wb
2
Plate Height (H)
Height equivalent to a theoretical plate
Small value is good
Resolution
R
N k
k
s
avg
=
−





+






4
1
1
2α
α
'
'
Large - good

20. Van Deemter Equation
H ~ A + B/µ + Cµ
H
µ