05-10-2012, 10:54 AM
INFRARED ABSORPTION SPECTROSCOPY
[attachment=35355]
INTRODUCTION
Spectroscopy is the study of the interaction of matter with the electromagnetic spectrum
The main goal is to determine the chemical functional groups in the sample
can accept a wide range of sample types such as gases, liquids, and solids
operate from radiation in the range from 1 to 25 micron wavelength
Frequency range 300-400thz (Tera hertz)
Infrared radiation is provided by an electrically heated source(tungsten, mercluryarc,carbondioxide laser source)
The IR Spectroscopic Process
The molecule absorb energy from the incident radiation which is essential to create the dipole moment change.
These vibrations have frequencies which depend on the force constant of the bond between atom and masses of the vibrating atoms
The IR Spectroscopic Process
When a wave of infrared light encounters this oscillating EM field generated by the oscillating dipole of the same frequency, the two waves couple, and IR light is absorbed
The coupled wave now vibrates with twice the amplitude
GENERAL USES
Identification of all types of organic and many types of inorganic compounds
Determination of functional groups in organic materials
Determination of the molecular composition of surfaces
Identification of chromatographic effluents
Quantitative determination of compounds in mixtures
Nondestructive method
Determination of molecular conformation (structural isomers) and stereochemistry (geometrical isomers)
Determination of molecular orientation (polymers and solutions)
APPLICATIONS
Identification of compounds by matching spectrum of unknown compound with reference spectrum (fingerprinting)
Identification of functional groups in unknown substances
Identification of reaction components and kinetic studies of reactions
Identification of molecular orientation in polymer films
Detection of molecular impurities or additives present in amounts of 1% and in some cases as low as 0.01%
Identification of polymers, plastics, and resins
Analysis of formulations such as insecticides and copolymers
[attachment=35355]
INTRODUCTION
Spectroscopy is the study of the interaction of matter with the electromagnetic spectrum
The main goal is to determine the chemical functional groups in the sample
can accept a wide range of sample types such as gases, liquids, and solids
operate from radiation in the range from 1 to 25 micron wavelength
Frequency range 300-400thz (Tera hertz)
Infrared radiation is provided by an electrically heated source(tungsten, mercluryarc,carbondioxide laser source)
The IR Spectroscopic Process
The molecule absorb energy from the incident radiation which is essential to create the dipole moment change.
These vibrations have frequencies which depend on the force constant of the bond between atom and masses of the vibrating atoms
The IR Spectroscopic Process
When a wave of infrared light encounters this oscillating EM field generated by the oscillating dipole of the same frequency, the two waves couple, and IR light is absorbed
The coupled wave now vibrates with twice the amplitude
GENERAL USES
Identification of all types of organic and many types of inorganic compounds
Determination of functional groups in organic materials
Determination of the molecular composition of surfaces
Identification of chromatographic effluents
Quantitative determination of compounds in mixtures
Nondestructive method
Determination of molecular conformation (structural isomers) and stereochemistry (geometrical isomers)
Determination of molecular orientation (polymers and solutions)
APPLICATIONS
Identification of compounds by matching spectrum of unknown compound with reference spectrum (fingerprinting)
Identification of functional groups in unknown substances
Identification of reaction components and kinetic studies of reactions
Identification of molecular orientation in polymer films
Detection of molecular impurities or additives present in amounts of 1% and in some cases as low as 0.01%
Identification of polymers, plastics, and resins
Analysis of formulations such as insecticides and copolymers