Ionization of PCBs using ion trap mass spectrometry

The toxicity of PCB mixtures is due principally to a small group of non-ortho and mono-ortho substituted congeners, usually present in environmental samples in lower concentrations than those of other congeners, thus the development of methods for toxic congener recognition is very important. The objectives of the present work were to compare quantitatively selected ion monitoring (SIM) of the electron impact (EI) mass spectra of PCBs with selected reagent ion chemical ionization (SRICI) mass spectra in terms of the detection limits achieved and to examine the possibility for distinguishing the more toxic congeners from those of lower toxicity. Since each ionization process determines the characteristics of the resulting mass spectrum, the task at hand was to identify from these mass spectra appropriate criteria for the determination of total PCB content and for differentiation of PCB congeners in order to determine the toxicity of PCB mixtures.