Differentiation Between Types of Dialkyl Phthalates Based on Their EI Mass Spectra

摘要

Although there are a few inconsistencies with respect to branched alky groups in esters of phthalate acid, the intensities of the m/z 167-peak in all bis(n-alkyl) phthalates indicates little or no ion current due to the loss of the H_2C=CHR molecule before dehydration of the hydrated O-substituted alkyl phthalic anhydride. It appears that a non linear configuration of one or both of the substituents promotes the formation of the hydrated protonated phthalic anhydride. This is supported by the results of Gaussian calculations for the two different ions.