Molecular ion stabilization for enhanced tandem mass spectrometry through derivatization for alkylphenols

While developing a residue method for the analysis of alkylphenols, such as nonylphenol (a class of endocrine disrupting chemicals), an unusual electron impact (EI) spectrum was obtained for nonyl phenylacetate (NPA). No molecular ion was observed, and a spectrum similar to that of the underivatized phenol was recorded, containing ions at m/z 220 and 107. This observation was explain by the loss of neutral ketene. Examination of the EI spectrum of NPA indicated an increase in the intensity of the m/z 220 ion when compared to that in the spectrum of NP. This increase in the intensity of m/z 220 was exploited to enhance tandem mass spectrometric analysis of NP.