Spectrometry and Infrared Spectroscopy

Mass Spectrometry and Infrared Spectroscopy 13-1 Chapter 13 Mass Spectrometry and Infrared Spectroscopy 

Infrared spectroscopy identifies functional groups. IR absorptions are reported in wavenumbers  

The functional group region from 4000-1500 cm is the most useful region of an IR spectrum. C-H, 0-H, andN-H bonds absorb at high frequency, a 2500 cm .  

As bond strength increases, the wavenumber of an absorption increases thus triple bonds absorb at higher wavenumber than double bonds. 

The higher the percent -character, the stronger the bond, and the higher the wavenumber of an IR absorption. 

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CHAPTER 12 Structure Determination Mass Spectrometry and infrared Spectroscopy... 

Kurt Varmuza was bom in 1942 in Vienna, Austria. He studied chemistry at the Vienna University of Technology, Austria, where he wrote his doctoral thesis on mass spectrometry and his habilitation, which was devoted to the field of chemometrics. His research activities include applications of chemometric methods for spectra-structure relationships in mass spectrometry and infrared spectroscopy, for structure-property relationships, and in computer chemistry, archaeometry (especially with the Tyrolean Iceman), chemical engineering, botany, and cosmo chemistry (mission to a comet). Since 1992, he has been working as a professor at the Vienna University of Technology, currently at the Institute of Chemical Engineering. 

Reactions were carried out in the liquid phase using 100 % HNOj from MERCK. Acidic clays (Slid CHEMIE - Munich FRG) and dessicants (PROLABO) were of commercial grade and used without further purifications, besides thermal treatments if needed. All compounds were analysed by gaz chromatography and their structures confirmed by mass spectrometry and infrared spectroscopy. 

Widely used techniques are GLC, HPLC, and TLC for general identification and quantitation, with mass spectrometry and infrared spectroscopy for specific identification. 

Regarding ozonation processes, the treatment with ozone leads to halogen-free oxygenated compounds (except when bromide is present), mostly aldehydes, carboxylic acids, ketoacids, ketones, etc. [189]. The evolution of analytical techniques and their combined use have allowed some researchers to identify new ozone by-products. This is the case of the work of Richardson et al. [189,190] who combined mass spectrometry and infrared spectroscopy together with derivatization methods. These authors found numerous aldehydes, ketones, dicarbonyl compounds, carboxylic acids, aldo and keto acids, and nitriles from the ozonation of Mississippi River water with 2.7-3 mg L 1 of TOC and pH about 7.5. They also identified by-products from ozonated-chlorinated (with chlorine and chloramine) water. In these cases, they found haloalkanes, haloalkenes, halo aldehydes, haloketones, haloacids, brominated compounds due to the presence of bromide ion, etc. They observed a lower formation of halocompounds formed after ozone-chlorine or chloramine oxidations than after single chlorination or chlorami-nation, showing the beneficial effect of preozonation. 

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