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Yutaka Terashima - One of the best experts on this subject based on the ideXlab platform.
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chlorine stable isotope measurements of chlorinated aliphatic hydrocarbons by thermal ionization mass spectrometry
Analytica Chimica Acta, 2002Co-Authors: Masahiko Numata, Noboru Nakamura, Hiromoto Koshikawa, Yutaka TerashimaAbstract:Abstract An improved method for chlorine isotopic analysis using thermal ionization mass spectrometry (TIMS) of Cs2Cl+ has been investigated. The δ 37 Cl values (parts per mil deviations from the standard seawater 37 Cl / 35 Cl ratio) for 10 commercial chlorinated aliphatic hydrocarbons (CAHs), provided by six suppliers are presented. The CAHs were treated with a sodiumbiphenyl reagent. The liberated Chloride ions were converted to CsCl and their isotopic compositions were determined by TIMS. Replicate analysis of the CAHs gave an external precision of 0.1–0.4‰ (1σS.D.). As each compound and each supplier has a distinctive δ 37 Cl value (δ 37 Cl values: −5.0 to +2.9‰), Cl isotope data can be used to trace a specific source of pollutants in the subsurface environment. Trichloroethene (TCE) and tetrachloroethene (PCE) were extracted from aqueous solutions with toluene and their chlorine isotope compositions were analyzed. The solvent extraction method presented here may be applicable to the analysis of actual contaminated water samples. Chlorine atoms were recovered as Inorganic Chloride from unsaturated chlorinated aliphatic compounds (TCE and PCE) by KMnO4 oxidation. However, the saturated compounds were resistant to KMnO4 oxidation. The isotopic compositions of the recovered Chloride ion were then determined by TIMS. It is suggested that such compound-specific isotopic analyses may give information about the past record of each contaminant.
Orjan Gustafsson - One of the best experts on this subject based on the ideXlab platform.
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chlorine isotope analysis of submicromole organochlorine samples by sealed tube combustion and thermal ionization mass spectrometry
Analytical Chemistry, 2004Co-Authors: Henry Holmstrand, Per Andersson, Orjan GustafssonAbstract:Improved sensitivity in the analysis of stable chlorine isotopes of organochlorines (δ37Cl−OCl) has been established using sealed tube combustion in conjunction with thermal ionization mass spectrometry (TIMS). TIMS of chlorine isotopes was performed on <85 nmol of Cl with an achievable precision of <0.25‰ for pure Inorganic Chloride samples and 0.46‰ for Chloride liberated from organochlorines (OCls). This makes possible significant reductions in the overall sample size requirement, as compared to the techniques of gas source stable isotope ratio mass spectrometry (SIRMS). Yields in excess of 99% were demonstrated in the dechlorination of <0.14 μmol 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT), and the overall yield, including purification of liberated Chloride, was 86−97%. The accuracy of TIMS in the measurement of chlorine isotopes derived from OCls was confirmed by analysis of a DDT sample previously analyzed with SIRMS.9 Using the described method for TIMS, the DDT sample gave a bulk chlorine ...
Noboru Nakamura - One of the best experts on this subject based on the ideXlab platform.
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chlorine stable isotope measurements of chlorinated aliphatic hydrocarbons by thermal ionization mass spectrometry
Analytica Chimica Acta, 2002Co-Authors: Masahiko Numata, Noboru Nakamura, Hiromoto Koshikawa, Yutaka TerashimaAbstract:Abstract An improved method for chlorine isotopic analysis using thermal ionization mass spectrometry (TIMS) of Cs2Cl+ has been investigated. The δ 37 Cl values (parts per mil deviations from the standard seawater 37 Cl / 35 Cl ratio) for 10 commercial chlorinated aliphatic hydrocarbons (CAHs), provided by six suppliers are presented. The CAHs were treated with a sodiumbiphenyl reagent. The liberated Chloride ions were converted to CsCl and their isotopic compositions were determined by TIMS. Replicate analysis of the CAHs gave an external precision of 0.1–0.4‰ (1σS.D.). As each compound and each supplier has a distinctive δ 37 Cl value (δ 37 Cl values: −5.0 to +2.9‰), Cl isotope data can be used to trace a specific source of pollutants in the subsurface environment. Trichloroethene (TCE) and tetrachloroethene (PCE) were extracted from aqueous solutions with toluene and their chlorine isotope compositions were analyzed. The solvent extraction method presented here may be applicable to the analysis of actual contaminated water samples. Chlorine atoms were recovered as Inorganic Chloride from unsaturated chlorinated aliphatic compounds (TCE and PCE) by KMnO4 oxidation. However, the saturated compounds were resistant to KMnO4 oxidation. The isotopic compositions of the recovered Chloride ion were then determined by TIMS. It is suggested that such compound-specific isotopic analyses may give information about the past record of each contaminant.
S K Frape - One of the best experts on this subject based on the ideXlab platform.
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determination of Inorganic chlorine stable isotopes by continuous flow isotope ratio mass spectrometry
Rapid Communications in Mass Spectrometry, 2005Co-Authors: Orfan Shouakarstash, R J Drimmie, S K FrapeAbstract:Chlorine stable isotope analyses of Inorganic samples were conducted using continuous flow isotope ratio mass spectrometry (CF-IRMS) coupled with gas chromatography (GC). Inorganic Chloride was precipitated in the form of silver Chloride (AgCl) by using silver nitrate in a standard methodology. Chlorine stable isotope analysis was carried out on methyl Chloride (CH3Cl) after converting AgCl into CH3Cl by reacting it with methyl iodide (CH3I). The reaction between AgCl and CH3I took place in 20 mL size vials. Addition of CH3I was performed in a glove bag under helium flow. An Agilent 6890 gas chromatograph equipped with a CTC Analytics CombiPAL autosampler and a DB-5MS 60 m column was used to separate CH3Cl from CH3I. This new technique uses samples as small as 0.2 mg of AgCl (1.4 μmol of Cl−). The chlorine stable isotope analysis using continuous flow technology showed excellent precision and accuracy. The internal precision using pure CH3Cl gas is better than ±0.04‰ (±STDV). The external precision using seawater standard is better than ±0.07‰ (±STDV) for n = 12. Moreover, the sample analysis time is much shorter and many more samples can be analyzed in one day than by using the conventional off-line techniques. Copyright © 2004 John Wiley & Sons, Ltd.
Masahiko Numata - One of the best experts on this subject based on the ideXlab platform.
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chlorine stable isotope measurements of chlorinated aliphatic hydrocarbons by thermal ionization mass spectrometry
Analytica Chimica Acta, 2002Co-Authors: Masahiko Numata, Noboru Nakamura, Hiromoto Koshikawa, Yutaka TerashimaAbstract:Abstract An improved method for chlorine isotopic analysis using thermal ionization mass spectrometry (TIMS) of Cs2Cl+ has been investigated. The δ 37 Cl values (parts per mil deviations from the standard seawater 37 Cl / 35 Cl ratio) for 10 commercial chlorinated aliphatic hydrocarbons (CAHs), provided by six suppliers are presented. The CAHs were treated with a sodiumbiphenyl reagent. The liberated Chloride ions were converted to CsCl and their isotopic compositions were determined by TIMS. Replicate analysis of the CAHs gave an external precision of 0.1–0.4‰ (1σS.D.). As each compound and each supplier has a distinctive δ 37 Cl value (δ 37 Cl values: −5.0 to +2.9‰), Cl isotope data can be used to trace a specific source of pollutants in the subsurface environment. Trichloroethene (TCE) and tetrachloroethene (PCE) were extracted from aqueous solutions with toluene and their chlorine isotope compositions were analyzed. The solvent extraction method presented here may be applicable to the analysis of actual contaminated water samples. Chlorine atoms were recovered as Inorganic Chloride from unsaturated chlorinated aliphatic compounds (TCE and PCE) by KMnO4 oxidation. However, the saturated compounds were resistant to KMnO4 oxidation. The isotopic compositions of the recovered Chloride ion were then determined by TIMS. It is suggested that such compound-specific isotopic analyses may give information about the past record of each contaminant.