High energy collisional spectroscopy of [RCOO]⁻ anions from negative ion chemical ionization of fatty acid methyl esters

Abstract

Abstract Saturated and mono‐unsaturated fatty acid methyl esters as well as corresponding underivatized acids gave abundant carboxylate anions [RCOO] − under negative ion chemical ionization (OH − and NH 2 − ) and electron attachment conditions. B/E or mass‐analysed ion kinetic energy spectra of fragments arising from high energy collision activated dissociation (CAD) of these [RCOO] − species contained decisive information on the original structure of the neutrals. From an analytical point of view, the method can utilize the gas chromatographic mass spectrometric combination and, in the B/E mode, can be used in practice on any double‐focusing mass spectrometer.