An online method to determine chlorine stable isotope composition by continuous flow isotope ratio mass spectrometry (CF-IRMS) coupled with a Gasbench Ⅱ  

作　　者：刘运德 周爱国 甘义群 刘存富 余婷婷 李小倩 

机构地区：[1]School of Environmental Studies,China University of Geosciences [2]State Key Laboratory of Biogeology and Environmental Geology (China University of Geosciences)

出　　处：《Journal of Central South University》2013年第1期193-198,共6页中南大学学报（英文版）

基　　金：Projects(40772156, 41072179) supported by the National Natural Science Foundation of China

摘　　要：An online method using continuous flow isotope ratio mass spectrometry （CF-IRMS） interfaced with a Gasbench Ⅱ was presented to determine chlorine stable isotope composition. Silver chloride （AgCl） was quantitatively derived from chloride by using silver nitrate （AgNO3）, and then was reacted with iodomethane （CH3Ⅰ） to produce methyl chloride （CH3Cl）. A GasBench Ⅱ equipped with a PoraPlot Q column was used to separate CH3Cl from any other gas species. Finally, chlorine stable isotope analysis was carried out on CH3Cl introduced to the IRMS in a helium stream via an active open split. The minimum amount of Cl used in this method is of the order of 1.4 μmol. Inter-laboratory and inter-technique comparisons show that the total uncertainty incorporating both the precision and accuracy of this method is better than 0.007%. Furthermore, ten seawaters sampled from different locations have a narrow δ37Cl value range from -0.008% to 0.010%, with a mean value of （0.000±0.006）%. This supports the assumption that any seawater can be representative of standard mean ocean chloride （SMOC） and used as an international reference material.An online method using continuous flow isotope ratio mass spectrometry (CF-IRMS) interfaced with a Gasbench Ⅱ was presented to determine chlorine stable isotope composition. Silver chloride (AgCl) was quantitatively derived from chloride by using silver nitrate (AgNO3), and then was reacted with iodomethane (CH3I) to produce methyl chloride (CH3Cl). A GasBench Ⅱ equipped with a PoraPlot Q column was used to separate CH3Cl from any other gas species. Finally, chlorine stable isotope analysis was carried out on CH3Cl introduced to the IRMS in a helium stream via an active open split. The minimum amount of Cl used in this method is of the order of 1.4μmol. Inter-laboratory and inter-technique comparisons show that the total uncertainty incorporating both the precision and accuracy of this method is better than 0.007%. Furthermore, ten seawaters sampled from different locations have a narrow δ 37 Cl value range from -0.008% to 0.010%, with a mean value of (0.000±0.006)%. This supports the assumption that any seawater can be representative of standard mean ocean chloride (SMOC) and used as an international reference material.

关 键 词：chlorine stable isotope continuous flow isotope ratio mass spectrometry CF-IRMS GasBench Ⅱ 

分 类 号：O613.42[理学—无机化学]