Determination of inorganic chlorine stable isotopes by continuous flow isotope ratio mass spectrometry.
Determination of inorganic chlorine stable isotopes by continuous flow isotope ratio mass spectrometry.
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DOI：
10.1002/rcm.1762
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发表时间：
2005-01
期刊：
影响因子：
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通讯作者：
O. Shouakar‐Stash;R. Drimmie;S. Frape
中科院分区：
文献类型：
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作者：
O. Shouakar‐Stash;R. Drimmie;S. Frape
采用连续流动同位素比值质谱联用技术（CF-IRMS）和气相色谱联用技术（GC）对无机样品进行了氯稳定同位素分析。在标准方法中，通过使用银以氯化银（AgCl）的形式沉淀无机氯化物。用碘甲烷（CH_3 I）将氯化银转化为氯甲烷（CH_3Cl），然后进行氯稳定同位素分析。AgCl和CH 3 I之间的反应在20 mL大小的小瓶中进行。在氦气流下在手套袋中进行CH 3 I的添加。使用配备有CTC Analytics CombiPAL自动进样器和DB-5 MS 60 μ m柱的Agilent 6890气相色谱仪将CH 3Cl与CH 3 I分离。这项新技术使用的样品小至0.2毫克氯化银（1.4微摩尔的Cl-）。采用连续流动技术进行氯稳定同位素分析，具有良好的精密度和准确度。使用纯CH 3Cl气体的内部精密度优于+/-0.04 ‰（+/-STDV）。对于n=12，使用海水标准的外部精密度优于+/-0.07 ‰（+/-STDV）。此外，样品分析时间短得多，一天可以分析更多的样品比使用传统的离线技术。
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 micromol 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 per thousand (+/-STDV). The external precision using seawater standard is better than +/-0.07 per thousand (+/-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.