Transcript No Slide Title

An Introduction to Chromatography
• What is chromatography?
• The separation of a mixture by distribution of its components
between a mobile and stationary phase over time
– mobile phase = solvent or gas
– stationary phase = column packing material
Purpose of Chromatography
• Analytical - determine chemical composition of a
sample
• Preparative - purify and collect one or more
components of a sample
Schematic of a Gas Chromatograph
Flow splitter
Two-stage
pressure
regulator
Rotameter
Syringe
Detector
Injector
Classification of Column Chromatographic Methods
General Classification
Liquid chromatography
(LC)
(Mobile phase: liquid)
Gas Chromatography
(GC)
Mobile phase: gas
Gas-liquid
Gas-bonded phase
Gas-solid
Flow controller
Carrier gas
supply
Specific Method
Liquid-liquid or
partition
Liquid bonded
phase
Liquid- solid or
adsorption
Ion exchange
Size exclusion
Column
Stationary Phase
Liquid adsorbed on solid
Organic liquids bonded on a
solid surface
Solid
Ion exchange resin
Liquid in interstices of a
polymeric solid
Liquid adsorbed on solid
Organic species bonded to a
solid surface
Solid
Type of Equilibrium
Partition between
immiscible liquids
Partition between liquid
and bonded phase
Adsorption
Ion exchange
Partition/sieving
Partition between gas and
solid
Partition between gas and
bonded phase
Adsorption
Temperature
controlled
zones
Carrier Gas Supply
Injector and Detector
300Vdc
300Vdc
Injection types
A Capillary Column for GLC
A thin layer of nonvolatile stationary
phase is coating on the inner wall of the
tubing (WCOT)
Fused silica tubing
dc  0.3 mm
df  1 m
L = 15 - 60 m
Polydimethylsiloxane (silicone)
• Good for retaining and separating
nonpolar solutes by boiling point
Some Common Stationary Phases for Gas-Liquid
Chromatography
Stationary phase
Common trade
name
Polydimethyl siloxane OV-1,SE-30
Poly(phenylmethyl
OV-3, SE-32
dimethyl) siloxane
(10% phenyl)
Poly(phenylmethyl)
OV-17
siloxane (50% phenyl)
Poly(trifluoropropyldi OV-210
methyl) siloxane
Polyethylene glycol
Carbowax 20M
Poly(
dicyanoallyldimethyl)
siloxane
OV-275
Maximum Common Applications
temperature
350
General purpose
nonpolar phase;
hydrocarbons;
polynuclear aromatics;
drugs; PCB”s
350
Fatty acid methyl esters;
alkloids; drugs;
halogenated compounds
250
Drugs; steroids;
pesticides; glycols
200
Chlorinated aromatics;
nitroaromatids; alkyl
substituted benzenes
250
Fatty acids; alcohols;
ethers; essential oils;
glycols
240
Poly unsaturated fayyt
acids; rosin acids; free
acids; alcohols
Si
O
Si
O
CH3
Si OH + Cl Si Cl
CH3
CH3
Si O Si Cl + CH3OH
CH3
OH
OH
OH
OH
Si
O
Si
O
CH3
Si O Si Cl
CH3
CH3
Si O Si OCH3
CH3
4
1 2
Isothermal
at 45oC
3
5
0
10
20
30
5
6
Isothermal
at 145oC
7
0
8
10
20
30
4
Programmed
from 30o to
180oC
Time
0
Temperature(oC) 30
1
2
3
5
6
10
60
7
20
90
120
150
9
8
30
180
Effect of temperature on gas chromatograms
Capillary GC-MS
GC
Quadruple MS
Transfer Line
Fused silica
Column
Data system
Packed column GC-MS Interface
Nozzel
Jet separator
From GC
Skimmer
To MS
Carrier
Sample
To vacuum
pump
Components of a Mass Spectrometer
10-5 to 10-8 torr
Gaseous
ion sources
Mass
analyzer
Ion
transducer
Ion
inlet
Vacuum
pump
Signal
processor
Sample inlet
• batch inlet
• direct probe inlet
• chromatographic inlet
Direct probe
A sample probe for inserting a sample directly into an ion source
Vacuum pump
Heating coil
Direct insertion probe
Ionization chamber
Heater
Shield
Filament
Electron beam
Repeller
1st accelerating slit
Focusing slit
Molecular leak
Anode
2nd accelerating slit
To mass
analyzer
Quadruple Mass Spectrometer
Ions with stable
trajectories
Ions with unstable
trajectories
Ion source
Dc and ac oltages
Continuous Dynode Electron
Multiplier
Resistive conductive
surface
2kV
GND