What are the common fragments in mass spectrometry for esters?

Common fragments in mass spectrometry for esters include the parent ion, alkyl cations, acylium ions, and alkoxy radicals.

In mass spectrometry, esters often produce a variety of fragments due to the cleavage of different bonds in the molecule. The most common fragments include the parent ion, which is the original molecule that has been ionised. This is often the largest peak in the spectrum and represents the molecular mass of the ester.

Another common fragment is the alkyl cation. This is formed when the ester molecule loses a molecule of carboxylic acid during ionisation. The resulting cation is a fragment that contains the alkyl group of the ester. For example, if the ester is ethyl acetate, the alkyl cation would be the ethyl group (C2H5+).

Esters also commonly produce acylium ions. These are formed when the ester molecule loses an alcohol molecule during ionisation. The resulting ion is a fragment that contains the acyl group of the ester. For example, if the ester is ethyl acetate, the acylium ion would be the acetyl group (CH3CO+).

Finally, esters can produce alkoxy radicals. These are formed when the ester molecule loses a molecule of acylium ion during ionisation. The resulting radical is a fragment that contains the alkoxy group of the ester. For example, if the ester is ethyl acetate, the alkoxy radical would be the ethoxy group (C2H5O).

In summary, the common fragments produced by esters in mass spectrometry are the parent ion, alkyl cations, acylium ions, and alkoxy radicals. These fragments are produced by the cleavage of different bonds in the ester molecule during ionisation, and their presence can help to identify the structure of the original ester.