VAPOUR PHASE CHROMATOGRAPHY

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VAPOUR PHASE CHROMATOGRAPHY
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CONTENTS

• INTRODUCTION
• PRINCIPLE
• INSTRUMENTATION
• ADVANTAGES LIMITATIONS
• APPLICATIONS
• CONCLUSION

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INTRODUCTION

• This is an analytical technique for the
  separation of a mixture of solutes by the
  differential movement of individual solutes
  through a porous medium,
• depends on four forces
• Rate of flow of solvent.
• Solubility of the substance in the
  solvent.
• Partition effects.
• Adsorption effects.

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PRINCIPLE

• Separation of the components by partition between
  the liquid on the porous support and the gas.
• M P is gas and S P is non volatile liquid on
  porous medium.

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INSTRUMENTATION

• Carrier gas
• Flow meters
• Injectors
• Columns
• Detectors

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CARRIER GAS

• Properties
• Must be chemically inert.
• Commonly used gases include nitrogen, helium,
  argon, and carbon dioxide, hydrogen.
• Also contains a molecular sieve to remove water
  and other impurities.

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FLOW METERS

• Flow meters (flow meters) and flow sensors are
  devices used for measuring the flow rate or
  quantity of a moving fluid or gas.

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COLUMNS

• TWO TYPES
• Packed columns
• Made of stainless steel or glass and contains a
  packing of finely divided, inert, solid support
  material (eg. diatomaceous earth) that is coated
  with a liquid or solid stationary phase.

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• CAPILLARY COLUMNS
• Made of fused-silica with a polyimide outer
  coating.
• These columns are flexible.

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COLUMN TEMPERATURE

• Must be controlled to within tenths of a degree.
• Depends on the boiling point of the sample.
• The sample results in an elution time of 2 - 30
  minutes.
• Minimal temperatures give good resolution, but
  increase elution times.

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SAMPLE INJECTION PORT
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SAMPLE INJECTION PORT

• The sample should not be too large, and should be
  introduced onto the column as a "plug" of vapor -
  slow injection of large samples causes band
  broadening and loss of resolution.
• The temperature of the sample port is usually
  about 50C.

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DETECTORS

• GENERAL PROPERTIES
• Respond to very small quantities of vapor
  contained in a permanent gas.
• Should be insensitive to changes in flow rate.
• Some detectors require no other gas than that
  used as the carrier gas.
• Capable of operating at least 200C higher than
  the maximum column temperature.

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KATHEROMETER DETECTOR

• Introduced by Ray.
• Earlier days, used for analysis of hydrocarbon
  gases.
• Considered to respond to a number of different
  physical properties of the eluent gas with no one
  property playing a major role.

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FLAME IONISATION DETECTOR

• The next detector to be reported which was
  developed by Scott.
• It is the forerunner to the flame ionization
  detector FID.

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APPLICATIONS

• Environmental Monitoring and Cleanup
• Criminal Forensics
• Law Enforcement
• Security
• Food, Beverage and Perfume Analysis
• Astrochemistry
• Medicine

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ADVANTAGES

• Very good separation
• Time (analysis is short)
• Small sample is needed ml
• Good detection system
• Quantitatively analyzed

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DISADVANTAGES

• Time
• Side reaction
• Loss of sample

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CONCLUSION

• Vapor phase Chromatography is one of the most
  important tools in chemistry because of its
  simplicity, sensitivity and effectiveness in
  separating components of mixtures.
• It is widely used for quantitative and
  qualitative analysis of mixtures and for the
  purification of compounds.

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• D.J.SRAVANTHI
• M.PHARM(ANALYSIS)
• BHARATH INSTITUTE OF TECHNOLOGY