Electron ionization and positive-ion chemical ionization mass spectra of N-(2-hydroxyethyl) alkylamides

Abstract

A family of 12 (7 saturated and 5 unsaturated) long chain fatty acid N-(2-hydroxyethyl)amides has been investigated by electron ionization (EI) and positive-ion chemical ionization (PICI) mass spectrometry. This paper presents the mass spectra and structures of the main ions obtained by El and PICI (using methane as reactant gas). The discussion of the fragmentation pattern is made in correlation with the methyl branch position in aliphatic compounds and the double bond position in monounsaturated compounds. A quantitative correlation of the ratio [M-H2O + H]+/[M-H2O-H]+, in the PICI mass spectra, with the number of double bonds, C atoms, and aliphatic H atoms is made.