河口水体中溶解CO_2及其稳定同位素在线同时测定的技术研究——吹扫-EA-IRMS联用法  

Simultaneous Analysis of Dissolved CO_2 and ^(13)C/^(12)C ratios in Estuarine Water Using a Modification on-Line Pretreatment System Connected to EA-IRMS

作　　者：陈锦芳[1] 曹建平[2] 纪丽红[2] 

机构地区：[1]集美大学生物工程学院,福建厦门361021 [2]厦门大学海洋学系,福建厦门361005

出　　处：《地球与环境》2012年第4期611-617,共7页Earth and Environment

基　　金：国家自然科学基金项目(51004053);福建省自然科学基金项目(2009J01033);厦门大学科技创新项目(XDKJCX20051007);集美大学预研基金资助项目(C60816);李尚大集美大学学科建设基金;中国科学院城市环境与健康重点实验室开放基金(KLUEH201110)

摘　　要：稳定碳同位素比值(13 C/12 C)是指示碳生物地球化学行为的有效指标。本研究研制并优化了CO2及其稳定同位素测定的吹扫预处理系统,将该系统与EA-IRMS联用实现了溶解CO2、其它形式DIC及二者碳同位素比值的在线同时测定,测得河口水样中易逃逸CO2及其它形式DIC的相对标准偏差分别为3.7%和3.0%;二者的δ13 C值的标准偏差分别为0.30‰和0.15‰。运用此法对九龙江9个站位表层水中不同形态DIC的碳同位素进行测定,得出易逃逸CO2的δ13 C平均值为-12.90‰,其他形式DIC的δ13 C平均值为-5.63‰。该法为水体中无机碳及其稳定碳同位素的测定研究提供了新途径。Abstract：Stable carbon isotope ratios （^13C/^12C） are a useful tooi to trace the carbon biogeochemistry process. In this paper, a new on line pretreatment system coupling elemental analyzer connected with isotope ratio mass spectrometry （EA-IRMS） system was developed and the optimum running conditions for the pretreatment system were investigated. Using this system, dis- solved free CO2 （DFC）, remainder DIC （non-DFC）, δ^13CDFC and δ^13Cnon-DFC were determined simultaneously, with a standard de- viation of ±0.3‰ for δ^13CDFC and ±0.15‰ for δ^13non-DFC, and with a relative standard deviation of ±3.7‰ for DFC and ±3.0% for non-DFC. δ^13CDFC and δ^13Cnon-DFC of 9 samples collected from Jiulong River Estuary, China, were also measured, with a mean value of -12.90‰ for δ^13CDFC, and of-5.63‰ for δ^13 Cnon-DFC. This method would provide a new approach to study DIC and carbon isotopes in water.

关 键 词：稳定碳同位素 溶解CO2 河口水体 

分 类 号：O615.4[理学—无机化学]