Real-time trace detection of vapor-phase elemental mercury and its compounds

Xiaomei Tong; Robert B. Barat; Arthur T. Poulos

doi:10.1117/12.372850

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21 December 1999 Real-time trace detection of vapor-phase elemental mercury and its compounds

Xiaomei Tong; Robert B. Barat; Arthur T. Poulos

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Proceedings Volume 3853, Environmental Monitoring and Remediation Technologies II; (1999) https://doi.org/10.1117/12.372850
Event: Photonics East '99, 1999, Boston, MA, United States

Abstract

The high toxicity of mercury species (elemental and compound) has prompted a demand for accurate, real-time inventory and control of their emissions. Our method of choice for mercury compound vapor is Photofragment Fluorescence spectroscopy. Target compound concentrations can be related to the fluorescence intensity from an excited fragment. Fragment identities and distributions, as revealed in the fluorescence spectrum provide information on the composition of the parent species. In the first experimental phase, a static cell (no flow) containing mercury compound (e.g. HgCl₂ vapor was probed with a deep ultraviolet (UV) laser to generate characteristic spectra. An atmospheric pressure flow cell was used in the second stage. Limits-of-detection have been estimated. Detection schemes have included both photomultiplier tube (with interference filter) and charge- coupled-device camera (with monochromator). To reduce fluorescence quenching, we have expanded an argon gas stream containing Hg vapor through a micro-jet into a vacuum. The jet is crossed with a laser beam at 253.7 nm to excite atomic fluorescence, which is distinguished from the background by time gating.

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Xiaomei Tong, Robert B. Barat, and Arthur T. Poulos "Real-time trace detection of vapor-phase elemental mercury and its compounds", Proc. SPIE 3853, Environmental Monitoring and Remediation Technologies II, (21 December 1999); https://doi.org/10.1117/12.372850

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