同位素 ›› 2015, Vol. 28 ›› Issue (1): 41-47.DOI: 10.7538/tws.2015.28.01.0041

• 稳定同位素制备及应用 • 上一篇    下一篇

GasBench Ⅱ-IRMS测定微量碳酸盐中碳氧同位素比值方法研究

梁翠翠1;尹希杰2;徐勇航2;李云海2   

  1. 1.厦门大学 海洋与地球学院,福建 厦门361005;2.国家海洋局 第三海洋研究所 海洋与海岸地质环境开放实验室,福建 厦门361005
  • 出版日期:2015-02-28 发布日期:2015-03-13

Analytical Method for Carbon and Oxygen Isotope of Small Carbonate Samples with the GasBench Ⅱ-IRMS Device

LIANG Cui-cui1;YIN Xi-jie2;XU Yong-hang2;LI Yun-hai2   

  1. 1.College of Ocean & Earth Sciences, Xiamen University, Xiamen 361005, China;2.Open Laboratory of Ocean & Coast Environmental Geology, Third Institute of Oceanography State Oceanic Administration, Xiamen 361005, China
  • Online:2015-02-28 Published:2015-03-13

摘要:

采用Delta V Advantage 质谱仪与GasBench Ⅱ在线制样装置,分别用12 mL和3.7 mL的样品瓶,对不同质量(5~50 μg)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40 μg,且用12 mL样品瓶进行酸化测试时,δ13C和δ18O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3.7 mL样品瓶,样品取样量在15~50 μg时,δ13C的内部标准偏差为0.01‰~0.07‰,δ18O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,GasBench Ⅱ在线制样装置可以通过改用3.7 mL样品瓶,实现对低至15 μg微量碳酸盐样品的碳氧同位素精确测量。同时,碳酸盐样品的质量与峰面积具有很好的线性关系(R2>0.993 2),表明该方法也可用于样品中碳酸盐含量的测定。

关键词: 微量碳酸盐, 碳氧同位素, GasBench Ⅱ-IRMS

Abstract:

An analytical method for measuring carbon and oxygen isotopic compositions of trace amount carbonate (>15 μg) was established by Delta V Advantage isotope Ratio MS coupled with GasBench Ⅱ. Different trace amount (5-50 μg) carbonate standard samples (IAEA-CO-1) were measured by GasBench Ⅱ with 12 mL and 3.7 mL vials. When the weight of samples was less than 40 μg and it was acidified in 12 mL vials, most standard deviations of the δ13C and δ18O were more than 0.1‰, which couldn’t satisfied high-precision measurements. When the weight of samples was greater than 15 μg and it was acidified in 3.7 mL vials, standard deviations for the δ13C and δ18O were 0.01‰-0.07‰ and 0.01‰-0.08‰ respectively, which satisfied high-precision measurements. Therefore, small 3.7 mL vials were used to increase the concentration of carbon dioxide in headspace, carbonate samples even less as 15 μg can be analyzed routinely by a GasBench Ⅱ continuous-flow IRMS. Meanwhile, the linear relationship between sample’s weight and peak’s area was strong (R2>0.993 2) and it can be used to determine the carbon content of carbonate samples.

Key words: trace carbonate, carbon and oxygen isotopes, GasBench Ⅱ-IRMS