Detection of chlorinated hydrocarbons via Laser-atomization/Laser-induced fluorescence |
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Authors: | J B Jeffries G A Raiche L E Jusinski |
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Institution: | (1) Molecular Physics Laboratory, SRI International, 94025 Menlo Park, CA, USA;(2) Present address: Department of Chemistry, Hamilton College, 13323 Clinton, NY, USA |
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Abstract: | Chlorinated hydrocarbons (CHC), photodissociated at 193 nm, are detected with high sensitivity by observing the atomic chlorine fragment via laser-induced fluorescence (LIF). Photofragment emission spectra from CH3Cl, CH2Cl2, CHCl3, CCl4, C2HCl3, and C2Cl4 demonstrate that photofragment fluorescence and chemiluminescence are negligible in the region 700–800 nm where the 3p
44p
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S
0 3p
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P fluorescence from atomic chlorine is detected. There is also negligible interference for photodissociation in Ar, N2, and air bath gases. Total CHC can be readily detected in air flows at mixing fractions less than 20 ppb and averaging times less than 1 minute. Techniques for considerable improvement in this detection limit are discussed.Supported by the NSF |
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Keywords: | 33 00 82 80 |
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