采用Delta V Advantage质谱仪与Gas Bench Ⅱ在线制样装置，分别用12mL和3．7mL的样品瓶，对不同质量（5～50eg）的碳酸盐标准样品（IAEA-CO-1）进行碳氧同位素组成测定。测试结果表明，当取样量小于40μg，且用12mL样品瓶进行酸化测试...采用Delta V Advantage质谱仪与Gas Bench Ⅱ在线制样装置，分别用12mL和3．7mL的样品瓶，对不同质量（5～50eg）的碳酸盐标准样品（IAEA-CO-1）进行碳氧同位素组成测定。测试结果表明，当取样量小于40μg，且用12mL样品瓶进行酸化测试时，δ^13C和r^18O测量结果的内部标准偏差一半以上大于0．1‰，不能满足测试要求。当改用3．7mL样品瓶，样品取样量在15～50μg时，δ^13C的内部标准偏差为0．01‰～0．07‰，δ^18O的内部标准偏差为0．01‰～0．08‰，满足测试要求。所以，当样品量较少时，Gas BenchⅡ在线制样装置可以通过改用3．7mL样品瓶，实现对低至15μg微量碳酸盐样品的碳氧同位素精确测最。同时，碳酸盐样品的质量与峰面积具有很好的线性关系（R^2〉0．9932），表明该方法也可用于样品中碳酸盐含量的测定。展开更多
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 ...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.展开更多
基金Projects(40772156, 41072179) supported by the National Natural Science Foundation of China
文摘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.
