principle of Gas chromatography

1. GC Basic Principles

2. What is chromatography
• Separation Science
• Organizing by size
• Organizing by boiling point
(vapor pressure)
• Organizing by solubility
Before
After

3. What is Gas Chromatography
• Performed in the vapor state
• Requires a mobile phase, gas
• Requires a stationary phase
• Molecules migrate between the phases

4. GC Instrument

5. Gas Chromatographic Equipment
AUTOSAMPLERS GC BASIC UNITS GC DETECTORS INTEGRATORS
MS DETECTORS
MS Detector
Autosampler
GC
Detector
Autosampler
Data
system
GC Basic
Unit
Gaschromatog.
DATA SYSTEMS
SAMPLE
PREPARATION
SYSTEMS
GC Basic
Unit
Data
system
SAMPLE
PREPARATION
AND INJECTION
SYSTEMS
CHROMATOGRAPHIC
SEPARATION
SYSTEMS
DETECTION &
IDENTIFICATION
SYSTEMS
DATA
SYSTEMS
GC/SA Benchtop GC/MS

6. GC Instrument : injector

7. Requirements for the ideal injector
• Capable to quantitative accept a broad volatility range of sample
components
– Low discrimination
• To handle dirty and clean matrices
– With dirty matrices reduces sample clean-up
– With clean matrices boosts sensitivity
• Extremely inert
– Able to handle polar/active compounds
• Provide optimum band shape

8. Vaporizing
Injectors:
SSL
PPKD
PKD
PTV
No-vaporizing
Injectors:
On-column
Injection techniques

9. Injectors
True cold on-column
split/
splitless
PTV Packed and
wide-bore
columns

10. General criteria for injection system selection
PTV PTV

11. PRIMARY COOLING
SYSTEM
SECONDARY COOLING
SYSTEM
SBP
Room
temperature Temp.
Liquid sample
droplets
Liquid sample
plug Liquid sample
film
1 2
Carrier
gas
Primary
cooling
system
Cooling fluid
(secondary
cooling)
Oven
temperature
3
Cold On-Column Injector

12. Split Injector
Additional
Insulating
Carrier
Septum
Purge
Split Line
Glass Liner
5 mm ID
Length of Column
Inside Injector = 40 mm
Capillary
Column
7001-1417
970810
50 mm
Syringe
Splitting Point
Liner
Carrier
Pathway
Column
Injector
Chamber
Terminal
Fitting

13. Splitless Injector
Carrier
Septum
Purge
Split Line
80 mm
Syringe
Length of Column
Inside Injector = 64 mm
Capillary
Column 77001-1416
970805
Additional
Insulating
Splitless
Liner

14. PTV Injector
Septum
purge
line
Splitting
line
Carrier
OVEN
Liner
Column
Carrier gas
inlet
Septum
Septum purge line
Splitting
line
FORCED AIR
COOLING
Heating
element

15. GC Instrument

16. GC Instrument : column oven

17. Automatic Column Characterisation

18. Automatic Column Characterisation

19. Injector Pressure Programming

20. GC Instrument

21. Detectors Overview

22. Detectors Principles

23. Detectors Characteristics
RESPONSE MECHANISM
• Concentration dependent: TCD, ECD, PID
• Mass rate dependent: FID, NPD, FPD
NON DESTRUCTIVE DESTRUCTIVE
• TCD, ECD, PID • FID, NPD, FPD
RESPONSE TYPE
• Universal: TCD, FID, (PID)
• Selective: ECD, NPD, FPD, (PID)

24. FID : Flame Ionization Detector
Air
Column
effluent
+Hydrogen

25. ECD : Electron Capture Detector
Radioactive
source
Outlet
Column effluent + make-up gas

26. NPD : Nitrogen Phosphorous Detector
Collecting
electrode
Heated
source
Air
Column effluent + Hydrogen

27. FPD : Flame Photometric Detector
Interference
filter
Photomultipier tube
Air
Column effluent
+ Hydrogen

28. PID : Photo Ionization Detector
Heat sink
Quartz cell
UV
lamp
GC column Exit tube

29. Application Note: Blood/Alcohol

30. Coupling Chromatography to
Mass Spectrometry
Separation plus identification

31. Source & Analyzer

32. TRACE DSQ components
Ion Source
Analytical
Quadrupole
Curved Quadrupole Pre-filter
Detector

33. Quadrupole Wiring
• X Quadrupole Rod Pair
• AC and pos DC Voltage
• Y Quadrupole Rod Pair
• AC and neg DC Voltage
0.5 1 1.5 2
Series1

34. Stability Regions
APEX (0.706, 0.23699)
YZ-stable
XZ-stable

35. Mathieu Parameters
RF = m r2 2
e 2qz
DC = m r2 2
e 4az
e = charge (constant =1)
m = Mass in kg
r = radius = distance between
rod inner surface and center
of quadrupole
w = 2 * frequency (1100 kHz)

36. DSQ II Single Quadrupole

37. Literature Available for DSQ II
• Confirmation of Drugs of Abuse Application/Technical Notes
Marijuana Cocaine
PCP Amphetamines Opiates