GAS CHROMATOGRAPHY

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GAS CHROMATOGRAPHY : 

GAS CHROMATOGRAPHY A SEMINAR ON Presented by ABDUL RAZZAQ 1st M.Pharm Dept. of Pharma.chemistry Under the Guidance of SYEDA HUMAIRA Luqman College Of Pharmacy Gulbarga

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GAS CHROMATOGRAPHY

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Principles Partition of molecules between gas (mobile phase) and liquid which is coated on to a solid support is used as stationary phase. The mixture of components to be separated is converted to vapour and mixed with gaseous mobile phase. GAS CHROMATOGRAPHY

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Gas Chromatography

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Detectors :- 1) Flame Ionization Detector 2) Thermal Conductivity Detector 3) Electron Capture Detector 4) Nitrogen phosphorus detector GAS CHROMATOGRAPHY

Thermal Conductivity Detector : 

Thermal Conductivity Detector GAS CHROMATOGRAPHY

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Measures the changes of thermal conductivity due to the sample (mg). Sample can be recovered. 1)Thermal Conductivity Detector GAS CHROMATOGRAPHY

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Principal: The thermal balance of a heated filament. Electrical power is converted to heat in a filament and the temperature will climb until heat power loss form the filament equals the electrical power input. The filament may loose heat by radiation to a cooler surface by conduction to the molecules which contact with the filament. GAS CHROMATOGRAPHY

Advantages : 

Advantages Applicable to most compounds. Linearity is good. The sample is not destroyed and hence used in preparative scale. Simple, easy to maintain and inexpensive. GAS CHROMATOGRAPHY

Disadvantages : 

Disadvantages Low sensitivity. Affected by fluctuations in temperature and flow rate. The response is only relative and not absolute. Biological samples cannot be analysed. GAS CHROMATOGRAPHY

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2) Flame Ionization Detector The ionisation detector are based upon the electrical conductivity of carrier gas. The carrier gas like hydrogen if in pure state does not induce current since there is no ionisation.When H2 is mixed with nitrogen or argon and passed in between platinum cathode and silver gauze anode will produce a current this can be amplified & recorded. GAS CHROMATOGRAPHY

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Exhaust Chimney Igniter Hydrogen Inlet Column Effluent Collector Electrode Schematic Diagram of Flame Ionization Detector GAS CHROMATOGRAPHY

Flame Ionization Detector : 

Flame Ionization Detector GAS CHROMATOGRAPHY

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It as got two electrodes with the column effluent passing between them. One of the electrode is treated with a radioactive isotope which emits electrons.These electrons are collected by the anode when potential of 20volt is applied.The difference of current is amplified &recorded as out put.The carrier gas can be argon,N2,H2 etc. 3) Electron Capture Detector :- GAS CHROMATOGRAPHY

Electron Capture Detector : 

Electron Capture Detector GAS CHROMATOGRAPHY

Electron capture detector : 

Electron capture detector GAS CHROMATOGRAPHY

Advantages : 

Advantages It is highly sensitive even nanogram quantities can be detected. Halogenated compounds, several pesticides, etc can be detected using this type of detector. GAS CHROMATOGRAPHY

Disadvantages : 

Disadvantages It can be used only for compounds with electron affinity. GAS CHROMATOGRAPHY

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It is also called as thermionic detector. It is a very sensitive, specific detector the design is based on the FID. Physically the sensor appears to be very similar to the FID but, in fact, operates on an entirely different. 4)Nitrogen phosphorus detector :- GAS CHROMATOGRAPHY

Nitrogen phosphorus detector : 

Nitrogen phosphorus detector

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It differs from that of the FID by a rubidium or cesium chloride bead contained inside a heater coil situated close to the hydrogen jet. The bead is situated above a jet and heated by a coil, over which the nitrogen carrier gas mixed with hydrogen passes. When a solute that contains nitrogen or phosphorus is eluted, the partially combusted nitrogen and phosphorus materials are adsorbed on the surface of the bead. The adsorbed material reduces the work function of the surface and thus, electron emission is increased and the current collected at the anode rises. GAS CHROMATOGRAPHY

Advantage : 

Advantage It is highly sensitive, than the electron capture detector. GAS CHROMATOGRAPHY

Disadvantages : 

Disadvantages The main disadvantage of this detector is that its performance deteriorates with time. GAS CHROMATOGRAPHY

Gas Chromatography Application : 

Gas Chromatography Application GAS CHROMATOGRAPHY

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Qualitative analysis Checking the purity of compound Presence of impurities Quantitative analysis Multicomponent analysis or Determination of mixture of drugs GAS CHROMATOGRAPHY

REFERENCES : 

REFERENCES Principles of instrumental analysis, 5 th edition,SKOOG, HOLLER, NIEMAN. Instrumental methods of analysis, 6 th edition, WILLARD, MERRIT, DEAN, SETTLE. Vogel's Textbook of Quantitative Chemical Analysis, J MENDHAM, RC DENNEY JD BARNES, MJK THOMAS. www.google.com

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THANK YOU