Spectroscopy of various types

Samples used for infrared analysis must be free from water because it absorbs so much radiation itself that it obliterates much information from other groups that might be present. Therefore samples of a material are dried and usually mixed with Nujol oil, or compressed with potassium bromide powder and put under great 

Many parts of organic molecules absorb light and so cause colour changes and wavelength shifts. The presence of certain groups in a molecule can be shown by reacting them with certain dyes. The intensity of the colour or absorption of the light is directly proportional to the amount of the materials present. 

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