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Chapter 14 Organic Chemistry: General uses for Infrared Spectroscopy
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Posted On :
Nov-19-2011
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Article Word Count :
470
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Here we will briefly discuss and summarize the general uses of IR and its common applications. We will aim to identify several types of organic and inorganic compounds as well as the determination of functional groups in organic materials. Infrared Spectroscopy will help to determine the molecular composition of surfaces, identify chromatograph effluents. The analytical procedure will also conclude the molecular conformation and orientation
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Here we will briefly discuss and summarize the general uses of IR and its common applications. We will aim to identify several types of organic and inorganic compounds as well as the determination of functional groups in organic materials. Infrared Spectroscopy will help to determine the molecular composition of surfaces, identify chromatograph effluents. The analytical procedure will also conclude the molecular conformation and orientation.
Infrared Spectrophotometers are designed to identify or determine the sample by measuring absorption of infrared radiation of wave numbers in a region of 4,000 to 400 cm-1, at various wave numbers when it passes through the sample. This method uses the property that the infrared absorption spectrum of a substance is characteristic of its chemical structure. Infrared spectra are shown in charts drawn by plotting the wave numbers on the abscissa and the transmittances or absorbance’s on the ordinate.
Some of the common applications will be to identify compounds by matching the spectrum of unknown compound with reference spectrum also known as fingerprinting. The goal will be to identify functional groups in unknown substances which we will examine. Unlike in flame spectroscopy IR spectroscopy can detect molecular impurities or additives present in as little as 1% or even in some cases as low as .01%.
Almost any solid, liquid or gas sample can be analyzed using various unique analytical equipment. For the purpose of this class the M530 IR Spectrophotometer from Buck Scientific will be used. A full list of the product specifications and instruction manual is available at our website. It will be crucial for the class to familiarize themselves with the all the necessary attributes and settings of the equipment.
The M530 uses a high energy optical design and a sensitive DLATGS detector for excellent resolution over the full infrared range. Maximum performance is achieved with a fast scanning mechanism which is completely microprocessor driven. This will allow for faster read outs and completion of more experiments than was possible before.
The limitations of such equipment are minimal elemental information given for most of the samples studied. Further complications may arise if the molecule is not in the active IR region. This means that when an element is exposed to IR radiation a minimum of one vibrational motion must alter the net dipole of the molecule in order for absorption to take place and be observed and analyzed.
In analysis of mixtures under favorable conditions we can most likely find that the accuracy is greater than 1%, as where in routine analysis it ± 5%. The main goal of IR spectroscopic analysis is to determine the chemical functional groups in the sample. Different functional groups absorb characteristic frequencies of IR radiation. Thus, IR spectroscopy is an important and popular tool for structural elucidation and compound identification.
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For more information visit Infrared Spectroscopy
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Keywords :
Infrared Spectroscopy ,
Category :
Reference and Education
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Science
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