Vacuum Ultraviolet Photon Ionization Mass Spectrometry for Detection of Dioxin Precursors

Waste incineration has been considered as a main source of dioxins. During the generation of dioxins, dioxin precursors, such as polychlorinated benzenes ( PCBz), polychlorinated phenols ( PCPh), polycyclic aromatic hydrocarbon ( PAHs), polychlorinated biphenyls ( PCBs) etc., have been proved to be produced with much higher concentrations than dioxins, which had been determined to be closely related to dioxin toxic equivalents. Therefore, online monitoring of these precursor compounds has been becoming one of the main research directions of dioxin detection. In this paper, we reported our attempt on developing a new method for online detection of these dioxin precursors in gas phase, by nanosecond vacuum ultraviolet single photon ionization technique, combined with time. of. flight mass spectrometer. This setup was evaluated by monitoring chlorobenzene, polychlorinated phenols and naphthalene in gas phase. In the range of 5-100 mu g/L, parent ion signal intensity of chlorobenzene exhibits linear dependence on the concentration.