Anomalies in the molecular ion region in the electron impact mass spectra of α‐ and β‐hydroxyesters

In the electron impact mass spectra of some alkyl α‐ and β‐hydroxyesters (introduced using the gas chromatography/mass spectrometry (GC/MS) technique), the absence of the molecular ion M +· and the presence of the [M + 1] + ion instead is observed. This phenomenon is especially characteristic of C 3 C 6 glycolates and diethyl malate, and is due to chemical auto‐ionization—ion‐molecule reactions in the high concentration gradient at the top of the GC peak. The existence of the [M 2] +· , [M −1] + and M +· ions in the mass spectra of other β‐ and α‐hydroxyesters is discussed.