Gas Chromatography

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Gas Chromatography
-??? ??-

• 2004.
• Kim, Wang-Yu Ph.D.
• Interface Engineering Co., Ltd.

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GC? ??

• ??? ?(???, ???) ???? ??? ??? ??? ??(?? ??)?? ???
  ?? ??? ???? ??? ??? ???? ??????? ????. ??????
  ???? ???? ?? ??? ???? ?? HPLC? ?? ?? ???.

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GC vs. LC
Gas
Liquid
Mobile phase
Sample state
Gas
Liquid
Stationary phase
Liquid
Liquid or solid
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Outside GC
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Inside GC
Injecting and vaporizing
Detecting
Separating
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Injection Port
Septum
Graphite ferrule
Nut
Inlet liner
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Septum
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Ferrule
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Capillary columns
1. Stationary phase 2. Inner Diameter(mm) 3.
Length(m) 4. Film Thickness(um)
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FID
Flame Ionization Detector
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(No Transcript)
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• GC Column ?? (??)

Open (Capillary)
Packed
Regular
Wall Coated
Open Tube (WCOT)
Bead
Porous
Conventional
Porous Layer
Column
Packed and
Layer
Open Tube (PLOT)
Micropacked
Bead
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• Capillary Column Types

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GC column? ??
1. Stationary phase
2. Inner Diameter(mm) 3. Length(m) 4. Film
Thickness(um)
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Polarity
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POLARITY
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DISPERSION INTERACTIONKcal/mole
DB-1 (non-polar)
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DIPOLE INTERACTIONCompounds With Dipole
Differences
H
H
Cl
H
CC
CC
H
Cl
Cl
Cl
1,2-dichloroethylene
1,1-dichloroethylene

• Smaller differences require a stronger dipole
  phase

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HYDROGEN BONDING INTERACTIONExample Compounds

• Strong alcohols, carboxylic acids, 1 and 2
  amines
• Moderate aldehydes, esters, ketones
• Weak hydrocarbons, halocarbons, ethers

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SELECTIVITYInteraction Strengths
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COMPOUNDSProperties
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50 CYANOPROPYL
1. Toluene2. Hexanol3. Phenol4. Decane
(C10)5. Naphthalene6. Dodecane (C12)
Strong DispersionStrong DipoleModerate H Bonding
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Polysiloxanes(Methyl Substituted)
of sites on silicon atoms occupied
100 methyl (HP-1, DB-1 etc.)
Nonpolar
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Polysiloxanes(Phenyl methyl Substituted)
5 phenyl (HP-5, DB-5, etc.)35 phenyl (HP-35,
DB-35, etc.)50 phenyl (HP-50, DB-17, etc.)
Nonpolar
Mid-polar
Mid-polar
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Polysiloxanes(Cyanopropylphenyl methyl
Substituted)
6 cyanopropylphenyl (HP-1301, DB-1301,
etc.)14 cyanopropylphenyl (HP-1701,
DB-1701etc.)50 cyanopropylphenyl (HP-225,
DB-225, etc.)
Mid-polar
Mid-polar
Polar
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HP-17 50 phenyl and 50 methyl
siloxanevsHP-50 (50)-Diphenyl
(50)-Dimethylpolysiloxane
Two columns are different !!
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Poly(ethylene) Glycol
n
100 PEG (HP-WAX) Less stable than
polysiloxanesUnique separation characteristics
Polar
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POLARITYSolubility And Retention
C12
C10
Hexanol
100 Methyl(non-polar)
0
2
4
6
8
Same GC conditions Same column dimensions Only
differ in stationary phase
C10
C12
100 PEG(polar)
Hexanol
0
2
4
6
8
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1. Stationary phase 3. Length(m) 4. Film
Thickness(um)
2. Inner Diameter(mm)
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COLUMN DIAMETERRetention80C isothermal
Isothermal Retention is inversely proportional
to column diameterTemperature program 1/3-1/2
of isothermal values
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COLUMN DIAMETER(0.050.53mm)
n 58,700
n 107,250
0.32 mm
0.53 mm
Sample capacity lt 2 ug
lt 500 ng
Instrumental condition
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• Phase Ratio

The
combined
effect
of
the
column
diameter
and
film
thickness
is
described
by
the
phase
ratio.
,

r/2d
f
where
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• Differing Column Inner Diameter, Equal Betas

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1. Stationary phase 2. Inner Diameter(mm) 4.
Film Thickness(um)
3. Length(m)
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COLUMN LENGTHTheoretical Efficiency
Length (m)
N
15
71,430
30
142,860
60
285,720
0.25 mm IDN/m 4762 (for k 5)
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COLUMN LENGTH(10120m)Resolution and Retention
Isothermal
15 m
60 m
30 m
Double the plates, double the time but not
double the the resolution
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1. Stationary phase 2. Inner Diameter(mm) 3.
Length(m)
4. Film Thickness(um)
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FILM THICKNESS(0.15um)Retention Isothermal
7.00
0.25 µm
0
2
4
6
8
Thermal stability Sample b.p.
25.00
1.00 µm
0
5
10
15
20
25
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FILM THICKNESSBleed
More stationary phase More degradation products
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Back biting Mechanism of Bleed Formation

Again
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Four Types Of Low Bleed Phases
Phases tailored to mimic currently existing
polymers -Examples DB-5ms, DB-35ms, DB-17ms New
phases unrelated to any previously existing
polymers -Example DB-XLB Optimized
manufacturing processes -Example DB-1ms
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Column Installation

• Choosing ferrule
• Cutting the capillary column
• Inlet installation
• Leak-checking
• Outlet installation
• Establishing flow
• Conditioning

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Ferrule

1. Choosing ferrule
2. Cutting the capillary column
3. Inlet installation
4. Leak-checking
5. Outlet installation
6. Establishing flow
7. Conditioning

• Graphite(100)
• - 450?
• - general purpose and reused
• - FID, NPD, ECD
• - Not good for Mass
• Vespel(100)
• - 280?
• - reused
• - for only isothermal operation

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Cutting

1. Choosing ferrule
2. Cutting the capillary column
3. Inlet installation
4. Leak-checking
5. Outlet installation
6. Establishing flow
7. Conditioning

• Jagged silica edges or exposed polyimide cause
  adsorption and tailing peaks, so it is very
  important that the column ends are cut uniformly.
  

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Inlet installation

1. Choosing ferrule
2. Cutting the capillary column
3. Inlet installation
4. Leak-checking
5. Outlet installation
6. Establishing flow
7. Conditioning

1. ?? column nut? capillary column? ??? ferrule?
   ???.
2. 3cm ?? capillary? ??? ? ? ?? inlet? ?? capillary?
   ferrule? ??? ??? ??.
3. ?? ??.
4. capillary? 5mm?? ???? ???.
5. ?? inlet? ????.
6. ??? ? ?? ???? ¼??? ? wrench? ???.
7. ???? ??? ? ? ??? Leak? ?? ?? injector ?? gauge?
   ???? ???.

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Leak-checking

1. Choosing ferrule
2. Cutting the capillary column
3. Inlet installation
4. Leak-checking
5. Outlet installation
6. Establishing flow
7. Conditioning

• Use acetone in vial

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Outlet installation

1. Choosing ferrule
2. Cutting the capillary column
3. Inlet installation
4. Leak-checking
5. Outlet installation
6. Establishing flow
7. Conditioning

• ?? detector jet orifice?? 1-3mm ???? column end?
  ?? ??(?? capillary? detector???? ??? ?? ?? ?? ?
  2mm?? ?? ??).
• column nut? ferrule? ??? ??? inlet? ??.

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Carrier gas Flow

1. Choosing ferrule
2. Cutting the capillary column
3. Inlet installation
4. Leak-checking
5. Outlet installation
6. Establishing flow
7. Conditioning

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Conditioning

1. Choosing ferrule
2. Cutting the capillary column
3. Inlet installation
4. Leak-checking
5. Outlet installation
6. Establishing flow
7. Conditioning

• 40? start and 510?/min
• below 2025?

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Storage

• septum on each end of the column
• Especially for PEG type column

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Split/Splitless Injection
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Splitless Injection
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And Now Lets do Some
TROUBLESHOOTING
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DB-624 COLUMN
QC Test Mix
2.71
Column DB-624 30m x 53mm I.D., 3.0µm Carrier
Helium at 40 cm/sec measured at
35C Injector Mega Direct, 260C Detector
FID, 300C Oven 35C for 1.50 min
30/min to 65 for 10 min
1. 1,2-Dichloropropane 2. Octane 3.
Tetrachloroethylene 4. Chlorobenzene 5. Nonane
8.0e4
7.0e4
6.0e4
7.43
10.92
5.0e4
4.0e4
17.42
12.49
3.0e4
20.78
2.0e4
1.0e4
5
10
15
20
25
Time (min.)
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Example of Column Contamination
2.21
1.5e4
1.4e4
DB-624 QC Test Mix After 75 Injections of
Oily Sample
1.3e4
3.30
1.2e4
1.1e4
1.0e4
6.03
9000
9.26
8000
10.46
14.40
7000
17.86
6000
0
5
10
15
20
Time (min.)
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Column and Liner Contamination
Inlet coil of column
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Example of Column Contamination
2.80
1.2e4
1.1e4
Removed 1 1/2 m from injector end
1.0e4
7.34
10.79
9000
17.19
8000
12.33
20.56
7000
6000
5000
0
5
10
15
20
25
Time (min.)
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Backflush Column
Rinse with 10ml each Methanol, Methylene
Chloride, Hexane
Capillary column
Special connectorand ferrule
Flexible teflontubing
Special adapter
1/16" flexible teflon line to regulated pressure
source
Cap
Vial
Beaker for solvent collection
Capillary column
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Remember
Complete system Carrier Gas Injector
Column Detector Data System
Multiple cause and effect Do not change too
many variables at once