天然海水硝酸盐氮同位素组成的蒸馏法测定

杨志; 陈敏; 曹建平; 邱雨生

天然海水硝酸盐氮同位素组成的蒸馏法测定

1.
厦门大学海洋学系, 福建厦门 361005
2.
厦门大学海洋学系, 福建厦门 361005;近海海洋环境科学国家重点实验室, 福建厦门 361005

基金项目: 科技基础性工作专项(2008FY110100);中国第4次北极科学考察计划;国际海底区域研究开发"十一五"项目(DYXM-115-02-4-06)。

计量
- 文章访问数: 1524
- HTML全文浏览量: 17
- PDF下载量: 2096
- 被引次数: 0
出版历程
- 收稿日期: 2011-09-06
- 修回日期: 2011-10-19

Ammonia distillation method for nitrogen isotope analysis of nitrate in seawater

1.
Department of Oceanography, Xiamen University, Xiamen 361005, China
2.
Department of Oceanography, Xiamen University, Xiamen 361005, China;State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005, China

摘要

摘要: 建立了测定天然海水中硝酸盐氮同位素组成的蒸馏法,该方法主要是在碱性条件下利用戴氏合金将海水中的硝酸盐还原为氨,后利用稀盐酸吸收生产的氨,将得到的氨吸收液浓缩后干燥结晶,利用同位素比值质谱仪测定所得晶体的氮同位素组成。研究中开展了戴氏合金添加量及氨吸收溶液在不同条件下干燥结晶对氮同位素测值的影响研究。结果表明,戴氏合金添加量为3.0 g及60 ℃下直接干燥结晶为最佳的实验条件。所建立的氨蒸馏法氮空白值仅为(0.90±0.19) μmol,低于此前文献报道的氮空白值;氮同位素组成(δ¹⁵N)空白值为(-14.7±4.1)×10^-3。运用所建立的氨蒸馏法实测得到的硝酸盐δ¹⁵N值与氨扩散法、硝酸盐直接测定法得到的数值非常吻合,进一步证明所建立氨蒸馏法的可靠性。改进后的氨蒸馏法适用于硝酸盐浓度在2~50 μmol/dm³内的天然海水硝酸盐氮同位素组成的测定,方法的标准偏差为±0.3×10^-3。
- 硝酸盐氮同位素组成 /
- 海水 /
- 氨蒸馏法
Abstract: A distillation method for determining ¹⁵N abundance of nitrate in seawater was set up in this study.The method mainly involved the conversion of nitrate to ammonia using Devarda's alloy and the trapping of the ammonia with diluted HCl.After drying,nitrogen isotopic composition of the ammonium salts was measured by an isotopic ratio mass spectrometer.In this study,the amount of Devarda's alloy for nitrate reduction and the conditions for ammonium salts drying were assessed.A total of 3.0 g of Devarda's alloy was needed to completely reduce nitrate to ammonia in 2 dm³ seawater,and the drying of ammonium salts at 60 ℃ was appropriate for sample preparation for isotopic measurements.The overall nitrogen blank of our method was (0.90±0.19)μmol,and lower than those reported previously.The δ¹⁵N value of nitrogen blank was( -14.7±4.1)×10^-3.Nitrogen isotopic composition determined by this method was well consistent with that measured by the ammonia diffusion method,demonstrating the reliability of this method.The ammonia distillation method was applicable for measurement of nitrogen isotopes in seawater with the nitrate concentration of 2~50 μmol/dm³.The precision for nitrogen isotope determination was within ±0.3×10^-3.
- Nitrogen isotopes of nitrate /
- seawater /
- ammonia distillation method

HTML全文

参考文献(25)

MCELROY M B.Marine biological controls on atmospheric CO₂ and climate[J].Nature,1983,302:328-329.

ALTABET M A,FRANCOIS R,MURRAY D W,et al.Climate-related variations in denitrification in the Arabian Sea from sediment ¹⁵N/¹⁴N ratios [J].Nature,1995,373:506-509.

FARRELL J W,PEDESON T F,CALVERT S E,et al.Glacial-interglacial changes in nutrient utilization in the equatorial Pacific Ocean [J].Nature,1995,377:514-517.

FALKOWSKI P G.Evolution of the nitrogen cycle and its influence on the biological sequestration of CO₂ in the ocean[J].Nature,1997,387:272-275.

ALTABET M A,HIGGINSON M J,MURRAY D W.The effect of millennial-scale changes in Arabian Sea denitrification on atmospheric CO₂ [J].Nature,2002,415:159-162.

BRANDES J A,DEVOL A H.A global marine-fixed nitrogen isotopic budget:implications for Holocene nitrogen cycling[J].Global Biogeochemical Cycles,2002,16(4),doi: 10.1029/2001GB001856.

HEATON T H E.Isotopic studies of nitrogen pollution in the hydrosphere and atmosphere:a review[J].Chemical Geology,1986,59:87-102.

CLINE J D,KAPLAN I R.Isotopic fractionation of dissolved nitrate during denitrification in the eastern tropical North Pacific Ocean[J]. Marine Chemistry,1975,3(4):271-299.

HORRIGAN S G,MONTOYA J P,NEVINS J L,et al.Natural isotopic composition of dissolved inorganic nitrogen in the Chesapeake Bay [J].Estuarine Coastal Shelf Science,1990,30:393-410.

LIU K K,SU M J,HSUEH C R,et al.The nitrogen isotopic composition of nitrate in the Kuroshio Water north-east of Taiwan:evidence for nitrogen fixation as a source of isotopically light nitrate[J].Marine Chemistry,1996,54:273-292.

WU J,CALVERT S E,WONG C S.Nitrogen isotope variations in the northeast subarctic Pacific:relationships to nitrate utilization and trophic structure [J].Deep-Sea Research,1997,44:287-314.

OSTROM N E,MACKO S A,DEIBEL D,et al.Seasonal variation in the stable carbon and nitrogen isotope biogeochemistry of a coastal cold ocean environment[J].Geochimica et Cosmochimica Acta,1997,61:2929-2942.

TANAKA T,SAINO T.Modified method for the analysis of nitrogen isotopic composition of oceanic nitrate at low concentration[J]. Journal of Oceanography,2002,58:539-546.

SUTKA R L,OSTROM N E,OSTROM P H,et al.Stable nitrogen isotope dynamics of dissolved nitrate in a transect from the North Pacific Subtropical Gyre to the Eastern Tropical North Pacific[J].Geochimica et Cosmochimica Acta,2004,68:517-524.

FISHER T R,MORRISSEY K M.A new method for the recovery of ammonium from natural waters for measurement of ¹⁵N composition in isotope dilution experiments[J].Marine Chemistry,1985,16:11-21.

KRISTIANSEN S,PAASCHE E.An improved method for determining relative ¹⁵N abundance in ammonium regeneration studies by direct diffusion [J].Marine Ecology Progress Series,1989,54:203-207.

LORY J A,RUSSELLE M P.Evaluation of diffusion method for preparing low nitrogen samples for ¹⁵N analysis[J].Soil Science Society of America Journal,1994,58:1400-1404.

SIGMAN D M,ALTABET M A,MICHENER R H,et al.Natural abundance-level measurement of the nitrogen isotopic composition of oceanic nitrate:an adaptation of the ammonia diffusion method[J].Marine Chemistry,1997,57:227-242.

SIGMAN D M,CASCIOTTI K L,ANDREANI M,et al.A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater[J].Analytical Chemistry,2001,73(17):4145-4153.

CASCIOTTI K L,SIGMAN D M,HASTINGS M G,et al.Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method[J].Analytical Chemistry,2002,74:4905-4912.

MCILVIN M R,ALTABET M A.Chemical conversion of nitrate and nitrite to nitrous oxide for nitrogen and oxygen isotopic analysis in freshwater and seawater[J].Analytical Chemistry.2005,77(17):5589-5595.

贾小妨,李玉中,徐春英,等,氮、氧同位素与地下水中硝酸盐溯源研究进展[J].中国农学通报,2009,25(14):233-239.

马传明,赵丽华,刘存富,等,天然水中硝酸盐氮氧同位素测试技术研究进展[J].工程勘察,2010,7:37-41.

LIU K K,KAPLAN I R.The eastern tropical Pacific as a source of ¹⁵N-enriched nitrate in seawater off southern California[J]. Limnology and Oceanography,1989,34:820-830.

SIGMAN D M,ALTABET M A,MCCORKLE D C,et al.The δ¹⁵N of nitrate in the Southern Ocean:nitrogen cycling and circulation in the ocean interior [J].Journal of Geophysical Research,2000,105:19599-19614.

施引文献

资源附件(0)

访问统计