Propionic acid mass spectrum

With short-chain acids, the loss of OH and COOH through a-cleavage on either side of the C=0 group may be observed. In the mass spectrum of propionic acid (Fig. 8.36), loss of OH... 

Halogenated aiyloxyphenoxypropionic acids are a new class of herbicides used for the selective removal of grass species. In commercial preparations, they are present as alkyl esters. In negative-ion ESI, haloxifop, fluazifop, and diclofop all show similar behaviour. The deprotonated molecule is the base peak in the spectrum. Weak formate and acetate adducts occur, and a fragment due to the loss of the propionate part [45]. The analysis of fluazifop and its butyl ester, fenoxaprop, quizalofop and haloxyfop and their ethyl esters, and diclofop and its methyl ester was reported. The free acids were analysed in negative-ion mode, and the esters in positive-ion mode. The esters showed sodium and potassium adducts next to the protonated molecules. The adduct formation was suppressed by the addition of 25 mmol/1 formic acid to the mobile phase. The influence of the orifice potential on the appearance of their mass spectra was studied [46-47]... 

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