Atomic composition can be determined by high-resolution mass spectrometry

Atomic composition can be determined by high-resolution mass spectrometry 

Element Isotope Mass number Exact mass 

For the bee pheromone on p. 48, the accurate mass turns out to be 114.1039. The table below  

Molecules with an odd molecular weight must have an odd number of nitrogen atoms. Molecules with even molecular weight must have an even number of nitrogen atoms or none at all. 

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ATOMIC COMPOSITION CAN BE DETERMINED BY HIGH-RESOLUTION MASS SPECTROMETRY... 

In high resolution mass spectrometry a mixed spectrum of an internal standard, normally perfluorkerosene, and of the sample is taken. Using the known masses of the internal standard, the accurate mass values of the sample ions are calculated. Their elemental compositions can then be determined by searching for the best fit of combinations of atomic mass... 

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