1. Lecture 7
Chromatography Intro!

2. Solid Phase Extraction
Load
(sample)
Eluent
(solvent)
Compounds of interest stick to sorbent
Compounds of interest released from sorbent
Waste
Extract

3. Compounds of interest in a plug
Chromatography
Mobile phase
Mobile phase
Load
Sample
(injection)
Compounds of interest in a plug
Differential interaction with stationary phase separates compounds in time and space.
Detector
Detector

4. Chromatography Definition
Separation of components in a mixture based on the differential movement through a porous media under the influence of a mobile phase

5. First Chromatography Column
toluene
sample

6. Liquid Chromatography
What happens in a chromatographic column?
Gas Chromatography
(GC)
Liquid Chromatography
(LC)
Distillation
Liquid-liquid
extraction

7. GC - gas chromatography
Theoretical Plate
GC - gas chromatography
open tubular columns
Silica support
Stationary phase
Gas (mobile phase)

8. LC - liquid chromatography
Theoretical Plate
LC - liquid chromatography
packed columns
Silica beads
Stationary phase
liquid (mobile phase)

9. Number of Theoretical Plates
Length of the column L
N = H
Height equivalent of a theoretical plate

10. tR-tM VR-VM k’ = = tM VM 1 < k’ < 10 Retention Factor
Describes the strength of the interaction of a compound with the stationary phase
tR-tM
VR-VM
k’ = = tM VM
1 < k’ < 10

11. Solid Phase Extraction
Load
(sample)
Eluent
(solvent)
k’ < 0.001
k’ > 1000
Compounds of interest stick to sorbent
Compounds of interest released from sorbent
Waste
Extract

12. Compounds of interest in a plug
Chromatography
Mobile phase
Mobile phase
Load
Sample
(injection)
1 < k’ < 10
Compounds of interest in a plug
Differential interaction with stationary phase separates compounds in time and space.
Detector
Detector

13. Retention Factor (k’)
Describes the strength of the interaction of a compound with the stationary phase

14. Effect of k’ on Selectivity and Resolution in LC
Retention Factor (k’)
Effect of k’ on Selectivity and Resolution in LC
Dong, M. Today’s Chemist at Work. 2000, 9(2),

15. Describes differential mobility of 2 compounds
Selectivity
Describes differential mobility of 2 compounds
k’2 K2
 = =
k’1 K1

16. Describes how well 2 compounds are separated
Resolution
Describes how well 2 compounds are separated
2(tR2-tR1)
Rs =
tw1+tw2

17. Describes how well 2 compounds are separated
Resolution
Describes how well 2 compounds are separated k’
1+k’ ( ) 1 4
Rs =
N1/2 (-1)
efficiency
selectivity
retention