Grantee Research Project Results
1998 Progress Report: Real-Time Trace Detection of Elemental Mercury and its Compounds
EPA Grant Number: R825380Title: Real-Time Trace Detection of Elemental Mercury and its Compounds
Investigators: Barat, Robert
Institution: New Jersey Institute of Technology
EPA Project Officer: Hahn, Intaek
Project Period: November 25, 1996 through November 24, 1998
Project Period Covered by this Report: November 25, 1997 through November 24, 1998
Project Amount: $199,121
RFA: Analytical and Monitoring Methods (1996) RFA Text | Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Environmental Statistics , Water , Air , Land and Waste Management
Objective:
The current research program has three major technical objectives:1) Design and fabricate a versatile supersonic jet fluorescence spectrometer; 2) Develop an effective method for extraction of the atomic Hg fluorescence signal from the resonant scattering background; and, 3) Test the effectiveness of photo-fragmentation fluorescence spectroscopy (PFFS) for speciating mercury compounds at low concentration.This program will determine the capabilities and limitations of mercury detection in real-time by the proposed techniques. It is anticipated that the detection limits for elemental mercury will be on the order of 0.1 microgram/cubic meter. It is desirable that response be linear up to about 5000 microgram/cubic meter. It is anticipated that PFF signals will successfully discriminate between species such as mercuric chloride and chloromethyl mercury at detection levels below 1 microgram/cubic meter.
Progress Summary:
The vacuum chamber and supersonic jet assembly are completed. Chamber optical access is complete. The UV light beam has been directed into the chamber to intersect the jet. Collection optics and light detection devices are assembled. Sources for producing gas streams containing elemental mercury or compound mercury have been fabricated. Preliminary experiments with argon containing Hg vapor expanded into the vacuum chamber have begun. The jet is intersected by a laser beam at 253.7 nm. Atomic fluorescence has been detected.Limits of detection have been estimated for PFF experiments in a separate, atmospheric pressure flow cell with mercuric bromide in argon. Analysis of the PFF signal has suggested that time gating of the collected light signal offers a relatively simple means for extraction of the mercury PFF signal from the resonant scattering background. Comparisons were made for PFF optical signal detection between interference filter+photomultiplier and monochromator+charge- coupled device (CCD) systems.
Future Activities:
In 1999, with a no-cost extension to November 30, several activities will be completed. Mercury bromide will be introduced into the chamber for PFFS experiments using a UV laser beam. A limit of detection will be estimated. Tests with elemental mercury will be completed. Time gating will be optimized. If interferometry proves useful in bench tests, a Michelson unit will be constructed and optically interfaced to the vacuum system.Journal Articles on this Report : 2 Displayed | Download in RIS Format
| Other project views: | All 4 publications | 2 publications in selected types | All 2 journal articles |
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Tong X, Barat RB, Poulos AT. A charge-coupled device-based laser photofragment fluorescence spectrometer for detection of mercury compounds. Review of Scientific Instruments 1999;70(11):4180-4184. |
R825380 (1998) R825380 (Final) |
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Tong X, Barat RB, Poulos AT. Detection of mercuric bromide in a gas phase flow cell by laser photofragment fluorescence spectroscopy. Environmental Science & Technology 1999;33(18):3260-3263. |
R825380 (1998) R825380 (Final) |
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Supplemental Keywords:
Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Water, Engineering, Mercury, Environmental Chemistry, Monitoring/Modeling, Environmental Monitoring, air quality, elemental mercury, high vapor pressure, industrial waste, waste combustion, doppler shifting, ambient particle properties, real-time monitoring, aerosol analyzers, air pollution, metalsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.