GAS chromatography ppt (Presentation) by Jatin Chauhan

This presentation covers the fundamental principles of Gas Chromatography (GC). Key topics include GC instrumentation, working, and diverse applications in science and industry. Essential resource for learning GC basics.
A concise overview of Gas Chromatography (GC) technology. It explains how GC works, detailing the components like the column, carrier gas, and detector. Includes practical examples of GC applications for compound separation and analysis.
Gas Chromatography

GC

Chromatography

Analytical Chemistry

Separation Science

Instrumentation

Analysis

PPT

Presentation

Chemistry

1. GAS CHROMATOGRAPY Presented by Jatin Chauhan M.Pharm (Pharmaceutics) 1 st semester Department of pharmaceutical Science Gurukula Kangri (Deemed to be University) 

2. Content:-

3. INTRODUCTION Gas chromatography is a common type of chromatography used for separating and analyzing compound in an unknown sample. In this method gas is used as mobile phase and solid or liquid is used as a stationary phase. In chromatography moving gas phase is passing over a stationary phase to separate the mixture compound. This method is first used by A.T James and P Martin in 1952 for separating long chain fatty acid.

4. Gas Chromatography Gas chromatography is an analytical method used to separate and analyze volatile organic substances. Also known as GLC (Gas-Liquid Chromatography), it falls under the category of partition chromatography. The system is composed of several key components: A carrier gas that acts as the mobile phase, continuously flowing through the system. An injection port where the sample is introduced. A separation column containing the stationary phase, where the compounds are resolved. An oven that maintains the column at controlled temperatures. A detector that identifies and quantifies the separated components.

5. Types of Gas Chromatography Gas Solid Chromatography Gas Liquid Chromatography M.P=Gas M.P=Gas S.P=Solid S.P=Liquid

6. Gas chromatography primarily exists in two forms: Gas-Solid Chromatography (GSC) Gas-Liquid Chromatography (GLC) Gas-Solid Chromatography This technique employs a solid stationary phase where the separation of components occurs due to their physical adsorption onto the solid surface. Gas-Liquid Chromatography This method is ideal for separating ions or molecules that are dissolved within a liquid solvent, utilizing a liquid stationary phase to achieve separation.

7. Principle of Gas Chromatography Gas ch romatography separates sample parts by how they split between a gas (mobile phase) and a liquid (stationary phase). It works on partition chromatography principles. The method uses gas as the mobile phase and a liquid on a solid as the stationary phase. Different organic compounds separate because they interact uniquely with these phases inside the column.

8. INSTRUMENTATION Carrier gas Sample injection port Columns Detectors Thermal conductivity (TC D) Electron capture detector(ECD) Flame Ionization detectoi ’ (Fl D) Flame photometric (FPD) Recorder

9. This Photo by Unknown Author is licensed under CC BY-SA-NC

10. Carrier gas The cylinder/ gas tank is fitted with a pressure controller to control the pressure of gas, a pressure gauge that indicates the pressure, a molecular sieve to transfer filtered dry gas and a flow regulator to ensure a constant rate of flow of mo bile phase to the column. It should meet the following criteria: Should be chemically inert Should be cheap and easily available. Should be of high quality and not cause any fire accidents. Should give best possible results. Should be suitable for the sample to be analyzed and for the detector,

11. Hydrogen, helium, nitrogen and carbon dioxide are commonly used. >Hydrogen has low density a nd better thermal conductivity. However, it reacts with unsaturated compounds and is inflammable and explosive in nature. >Nitrogen is inexpensive . -He is the most preferred gas. -Inlet pressure ranges from: 10-50 psi -Flow r ate : 25-150 m L/min for packed columns -flow rate: 2-25 m L/min for open tubular column.

12. Sample Injection port Sampling unit or injection port is attached to the column head. Since the sample should be in vaporized state, the injection port is provided with an oven that helps to maintain its temperature at a bout 20-50 *C above the boiling point of the sample. Gaseous samples may be introduced by use of a gas tight hypodermic needle of 0.5 -10 ml capacity. For Liquid samples , micro syringes of 0.1-100u L capacity may be used.

13. Injections of samples into Capillary Columns a . Split injections- it splits the volume of sample stream into two unequal flows by means of a needle valve , and allow the smaller flow to pass on to the columns and the bigger part is allowed to be vented to the atmosphere. This technique is not suitable whRn highest sensitivity is required .

14. b. Split less in jectors - They allow all of the sample to pass through the column for loading. Sample should be very dilute to avoid overloading of the column and a high capacity column such as SCOT or heavily coated WCOT columns should be used. C. On column injector : A syringe with a very fine quartz needle is used. Air cooled to - 20 ° C below the b.p. of the sample. After then the warmer air is circulated to vaporize the sample.

15. d.Automatic injector : For improving the reproducibility and if a large number of samples are to be analyzed or operation is required without an attendant, automatic injectors are used. The solid samples are introduced as a solution or in a sealed glass ampoule, crushed in the gas stream with the help of a gas tight plunger, and the sample gets vapourized and flows into column under the influence of carrier gas.

16. Column Unit Columns are of different shapes and sizes that includes: “U” tube type or coiled helix type. They are mainly made of copper, stainless steel, aluminum , Glass, nylon and other synthetic plastics. Support material:- it's main function is to provide mechanical support to the liquid phase. An ideal support should have a large surface area, chemically inert, should get uniformly wet with liquid phase, should be thermostable. Commonly used solid phases are: diatomaceous earth , glass beads, porous polymers, sand ,etc.

17. I•Types of columns:- There are two general types of columns: Packed columns:- In GLC, they are densely packed with finely divided, inert, solid support material ( diatomaceous earth) coated with liquid stationary phase. In GSC, the columns are packed with adsorbents or porous polymers. Length- 1.5-10m internal diameter- 2 - 4mm. Capillary columns- length ranges from 1 0-100 m inner diameter is usually 0.1-0.5mm.

18. Detector The eluted solute particles along with the carrier gas exit from the column and enter the detector. The detector then produces electrical signals proportional to the concentration of the components of solute. The signals are amplified and recorded as peak at intervals on the chromatography.

19. Properties of an ideal detector: Sensitive Operate at high T (o-4OO°C) Stable and reproducible Linear response Wide dynamic range Fast response Uniform response to all analyses

20. Flame Ionization detector Flame ionization detector is the most wildly used and generally applicable detector for gas chromatography. The effluent from the column is mixed with hydrogen and air and then ignited electrically Most organic compound when pyrolyzed at the temperature of hydrogen/air flame , produce iron and electron that can conduct electricity through the flame.

21. Electron capture detector (ECD) An electron capture detector (ECD) is a highly sensitive detector used in gas chromatography to detect electronegative compounds, such as halogenated compounds and pesticides, at trace levels. It works by using a radioactive source to generate electrons in a gas, which creates a steady current. When an analyte that can capture electrons passes through the detector, it reduces the number of free electrons, causing a decrease in the current that is measured.

22. >When only carrier gas flows heat loss to metal block is constant, filament T remains constant. > When an analyte species flows past the filament generally thermal conductivity changes, thus resistance changes which is sensed by Wheatstone bridge arrangement. > The imbalance between control and sample filament temperature is measured and a signal is recorded.

23. Applications Environmental analysis Waste and toxins : It can identify unknown organic compounds in hazardous waste and analyze pesticides and fertilizers . Water and air quality : GC is used to quantify pollutants in drinking and waste water, and to analyze air samples for quality control and to identify toxins.

24. Pharmaceutical and food industries Quality control : GC is used to test the quality and safety of pharmaceutical products and for quality control in the food industry. Food analysis : It can quantify carbohydrates, proteins, fats, vitamins, and contaminants in food. Identification : It can identify and quantify flavors, fragrances, and other volatile organic compounds.

25. Forensics and clinical Forensic analysis : GC is used to determine blood alcohol content and to identify drugs in body fluids and at crime scenes. Clinical analysis : It can analyze blood, saliva, and other secretions to identify drugs and other volatile organic compounds in the body.

26. THANK YOU