Gas chromatography (Liquid and solid) .pptx

Gas chromatography is a dynamic method of separation and detection of volatile organic compounds and several inorganic permanent gases in mixture.
When stationary phase is non volatile liquid coated on inner support and the mobile phase is gas, then the technique is called as gas liquid chromatography.
It is a partition type of chromatography
It is the commonly used gas chromatography.
When stationary phase is solid of a large surface area and the mobile phase is gas, then the technique is called Gas Solid Chromatography.
Silica gel, Alumina, Charcoal, etc. used as a stationary phase.
Gas chromatography deals with different types of chromatography and parts of gas chromatography instrument.

1. Gas chromatography PRASUN TM Dept. of Molecular Biology Kannur University

2. What is Gas Chromatography ? Gas chromatography is a dynamic method of separation and detection of volatile organic compounds and several inorganic permanent gases in mixture.

3. Gas Liquid Chromatography (GLC) When stationary phase is non volatile liquid coated on inner support and the mobile phase is gas, then the technique is called as gas liquid chromatography. It is a partition type of chromatography It is the commonly used gas chromatography.

4. Gas Solid Chromatography (GSC) When stationary phase is solid of a large surface area and the mobile phase is gas, then the technique is called Gas Solid Chromatography. Silica gel, Alumina, Charcoal, etc. used as a stationary phase.

5. Diagram of Gas Chromatography

6. Gas Chromatography Instrument

7. Mobile phase Mobile phase is a carrier gas , They are: Hydrogen Nitrogen Helium Carbon dioxide Argon Function of carrier gas  carry the sample through the system Helium is mostly used carrier gas due to its high thermal conductivity and low density which contribute to efficient separation and sensitive detection.

8. Diagram of Gas Chromatography

9. Sample Injection Port Micro syringe is commonly used. It involves the injection of 1 μ L to 3 μ L of a liquid sample into a heated inlet. The injection port allows entire volume of sample injected to be mixed with carrier gas and introduced into column for analysis.

10. Stationary Phase/Column Column is responsible for the separation of the components in the mixture. Chromatographic columns vary in length from less than 2 m to 50 m or more. They are made-up of stainless steel, glass, fused silica or Teflon. Column temperature is an important variable aspects of precise work. Column is housed in a thermostated oven.

11. Diagram of Gas Chromatography

12. Column

13. Capillary column

14. Effect of temperature on gas chromatograms

15. Column Columns are of two types: Packed column Capillary column / Open tubular column. The capillary column has become the column of choice due to the ability for high quality separations.

16. Capillary / Open Tubular Column Capillary columns are : Wall-Coated Open Tubular (WCOT) column Fused-Silica Open Tubular (FSOT) column Support-Coated Open Tubular (SCOT) column Porous Layer Open Tubular (PLOT) column

17. Fused-Silica Open Tubular (FSOT) column

18. Properties and Characteristics of typical GC Columns

19. Packed column It is fabricated from glass or metal tubing: They are typically 2 - 3 m long Inside diameters of 2 - 4 mm These tubes are densely packed with a uniform. The tubes are formed into coils with diameters of 15 cm approx.

20. Packed column

21. Packed column

22. Solid Support Materials The earliest and still the most widely used packing's for GC is Diatom.

23. Liquid Stationary Phase Properties of liquid phase in GC: Low volatility Thermal stability Chemical inertness

24. Liquid Stationary Phase

25. Diagram of Gas Chromatography

26. Detectors It is a device that senses the presence of components different from the carrier gas and converts that information to an electrical signal. Characteristics of detector: Selectivity – Ability of the detector to recognize and responds to the components of interest. Sensitivity – it is the concentration level detected and formally is defined as the change in the response with the change in detected quantity.

27. Types of detectors Thermal Conductivity Detector (TCD) It is the oldest type of GC detector used. Its able to respond to any type of constituent that is different from the carrier gas.

28. Types of detectors Flame Ionization Detector (FID) Organic components burns in a flame, produced ions that are collected and converted into a current. This is the most widely used now. Because it detects fairly low limits and responds to any type of hydrocarbon component.

29. Types of detectors Mass Selective Detector (MSD) Molecules are bombarded with electrons, producing ion fragments that pass into the mass filter. The ions are filtered based on their mass/charge ratio. This technique yields excellent qualitative identification of components by matching the compound’s mass spectrum with spectra included in libraries that are part of the system.

30. Types of detectors Photoionization Detector (PID) Infrared Detectors (IRD) Atomic Emissions Detectors (AED) Electron Capture Detector (ECD) Nitrogen-Phosphorous Detector NPD) Flame Photometric Detectors (FPD) Electrolytic Conductivity Detectors (ELCD)

31. Data Acquisition The last major component of the GC system is data Acquisition. The data system is used to translate the electrical signal generated by the detector into a peak chromatogram.

32. Gas chromatogram.

33. Working of Gas Chromatography High pressurized carrier gas is introduced to system from a cylinder. Pressure of gas is controlled by a regulator. Sample is injected to the heating inlet chamber by a syringe. Sample gets vaporised and mixed with carrier gas. The mixture moves through long packed coiled column of liquid stationary phase. The component separates due to the differential partitioning between the carrier gas and thin layer of liquid.

34. Working of Gas Chromatography The different components reaches at the outlet of the column at different time. Each components are detected using a sensitive detectors. The detector send signal to recorder after amplifying the signal. The recorder draws a plot . Were, intensity plotted against time. This plot is known as gas chromatogram.

35. Diagram of Gas Chromatography

36. Applications of Gas Chromatography Separation of complex organic and biochemical system To check the purity of organic compounds Petroleum, petrochemical industries Biomedical analysis Manufacturing of medicine.

37. Reference Fundamentals of analytical chemistry 8 th edition Skoog|West|Holler|Crooch Bio instrumentation L Veerakumari Biophysics Vasantha Pattabhi , N Goutham

38. Thank you PRASUN TM Dept. of Molecular Biology Kannur University