Stable Isotopes Classification According to Natural Abundance

1 Stable isotopes classification according to natural abundances 

A chemically pure organic compound will give a mixture of mass spectra because the elements that compose it are not isotopically pure. Recall the case of the element neon, which Sir J. J. Thomson (1913) showed gave not one peak at its chemical atomic weight of 20.2, but two peaks at masses 20.0 and 22.0, in relative abundances of 10 1. Of the common elements encountered in organic compounds (shown in Table 2.1, inside the front cover), many have more than one isotope of appreciable natural abundance. The isotopic abundances of other 

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