6.8 Identification of Compounds

The ability to identify unknown samples is one of the most powerful uses of a mass spectrometer.  This, however, requires an understanding of fragmentation patterns for commonly encountered compounds.  The following trends are only applicable to electron impact with a source at 70 eV.  These trends are not comprehensive but are rather a selection of common fragments that are most useful in properly identifying common types of organic chemicals. 

The actual likelihood of fragmentation is related to the activation energy of the reaction, the ability for a tight complex to form, and the stability of the products.  Trends that were observed in organic chemistry are helpful in predicting fragmentation patterns.  Thinking about the stability of the products as more or less stable cations and radicals is not entirely theoretically accurate but is usually a good, practical way to predict the spectrum of a molecule.

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Section 6.9

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