1. Gas Chromatography
Compiled by : Imanuelle Orchidea
3325102413

2. Definition
• A chromatographic technique in which the
mobile phase is a gas
Gas
Gas –Liquid/
Gas-Solid
Chromatography
Liquid
Solid

3. Rangkaian
penghubung &
penguat
Tabung gas
perekam

4. Mobile phase
• Inert gas ( He, Ar, N2)
• Carry the sample
• Flow rates determined with a flow meter
placed at a column outlet
Column type
Flow rate
Packed column
25-150 mL/min
Capillary column
1-25 mL/min

5. Packed columns
Capillary columns

6. Packed Columns
– Glass/stainless steel/copper/aluminum
– 2-6 m in length, internal Ø 2-4mm
– Particle Ø ranging from 37-44 µm to 250-354 µm
– diatomaceous earth, glass beads, fluorocarbons
polymers
– Handle larger samples
– Pressure needed to move mobile phase limits it’s
length

7. Capillary Columns
• Open tubular column
– Wall-coated
– Support-coated
• Fused silica coated with protective polymer
• Up to 100 m in length
• Internal Ø 150-300 µm, megabore up to 530
µm
• Handle smaller samples ( < 10-2 µL)

8. • Photo of capillary column, taken from Harvey,
David .T. Modern Analytical Chemistry

9. Stationary phase
• Choice of stat. phase  selectivity
• Criteria :
– CHEMICALLY INERT
– THERMALLY STABLE
– LOW VOLATILITY
– APPROPRIATE POLARITY
• R – SiR2 – O - (SiR2 – O)n – SiR3
• HO – CH2 – CH2 – (O – CH2 – CH2)n – OH

10. STAT.PHASE
POLARITY
TRADE NAME (T)LIMIT
APPLICATIONS
Squalane
Non-polar
Squalane
150
Low boiling aliphatic hydrocarbons
Apezion L
Non-polar
Apezion L
300
Amides
Fatty acid methyl esters
High boiling aliphatic HC
Terpenoids
Polydimethyl
siloxane
Slightly
SE-30
300-350
Alkaloids*
Amino acid derivatives **
Drugs# pesticides##
Phenols & steroids
50% methyl50%phenyl
polysiloxane
Moderate
OV-17
375
*, #, ##, Polyaromatic
hydrocarbons
Polychlorinated biphenyls
50%TFP50%MPSO
Moderate
OV-210
275
*,**, #, halogenated compounds,
ketones, phenols
50% CYP-50%
phe-me-PSO
Polar
OV-225
275
Nitriles, pesticides, steroids
PEG
Polar
Carbowax
20M
225
Aldehydes, esters, ethers, phenols

11. Introduction of samples
1. All constituents must be volatile
2. Appropriate concentration
3. Must not degrade the separation
Volatile analyte from Non volatile matrix:
1.
2.
3.
4.
Liquid-liquid extraction
Solid phase extraction  SPME
Headspace sampling
Cryogenic focusing

12. Injecting the sample
• Split injection
• Splitless injection
• On-column injection
Schematic diagram of an injector
for packed column GC

13. Detectors in GC
Thermal Conductivity

14. Another detectors
•
•
•
•
Flame photometric detector
Thermionic detector
FT-IR (GC-FT-IR)
MS (GC-MS)

15. Quantitative applications
•
•
•
•
Environmental analysis
Clinical analysis/forensic may include
Consumer goods
Petroleum industry