吹扫捕集-气相色谱法同时测定海水中的氟氯烃和六氟化硫  

Simultaneous Determination of Chlorofluorocarbons and Sulfur Hexafluoride in Seawater Based on a Purge and Trap Gas Chromatographic System

作　　者：蔡明刚[1,2] 邓恒祥 黄鹏[1] 柯宏伟[1] 郑雪红[1] 李文权[1] 

机构地区：[1]厦门大学海洋与地球学院,厦门361102 [2]厦门大学近海海洋环境科学国家重点实验室,厦门361102

出　　处：《分析化学》2016年第7期1003-1008,共6页Chinese Journal of Analytical Chemistry

基　　金：国家自然科学基金项目(Nos.40976113;41076133;91228202);南北极环境综合考察与评估专项(Nos.CHINARE2014-03-04-03;CHINARE2015-03-04-03);国家海洋局海洋-大气化学与全球变化重点实验室开放基金课题(No.gcmac1404);福建省"新世纪优秀人才支持计划";厦门大学校长基金资助~~

摘　　要：氟氯烃(CFCs)和六氟化硫(SF_6)都是人工合成的卤代化合物,在海洋科学考察中是非常重要的基础观测参数,在示踪海/气交换、水团交换等一系列重要海洋学过程研究中均有特殊的应用价值;同时,也可以用于估算表观耗氧速率(Apparent oxygen utilization rate,AOUR)以及人为碳(Anthropogenic CO_2,C_(ant))等一些重要的物理及生物地球化学过程参量。CFCs,SF_6在海水中的浓度非常低,测量难度大,而CFCs和SF6的联合使用对海洋学过程研究具有重大意义。本研究建立了一套吹扫捕集系统以分析海水中CFC-12和SF_6,对吹扫捕集系统测定条件进行了优化,最佳的实验条件为:捕集温度!70℃,吹扫时间8 min,吹扫压力310 kPa,脱附时间30 s,脱附温度90℃。本方法测定简单、灵敏度高,CFC-12和SF_6的检出限分别为0.02 pmol/kg和0.03 fmol/kg,CFC-12和SF6的测定精密度分别为±1.2%和±0.5%。标准工作曲线的线性相关系数均大于0.9995。本方法成功应用于2014年中国第六次北极科学考察航次中采集的海水样品的测定。Chlorofluorocarbons （CFCs） and sulfur hexafluoride （ SF6 ） are kinds of anthropogenic halogenated compounds. They are very important for the ocean processes including air-sea exchange, water mass exchange etc. Meanwhile, they can be used to calculate some key physical and biogeochemical parameters such as AOUR （apparent oxygen utilization rate） and Cant （anthropogenic CO2 ）. In comparison with CFCs, it is quite difficult to measure SF6 in the seawater due to its low solubility. However, it is useful to study the oceanic processes based on both the CFCs and SF6. In this study, a purge and trap gas chromatographic system was developed to measure the CFC-12 and SF6 simultaneously in seawater. The optimum conditions were as follows： trap temperature of-70℃, purge time of 8 min, purge gas pressure of 310 kPa, desorption time of 30 s, and desorption temperature of 90℃. The detection limit of CFC-12 and SF6 were 0.02 pmol/kg and 0.03 fmol/kg, respectively. The analytical precisions of CFC-12 and SF6 were ± 1.2% and ±0.5%, respectively. The correlation coefficients （ R2 ） of all the calibration curves were greater than 0. 9995. This method was successfully used in the analysis of the samples collected from 6th Chinese Arctic Research Expedition.

关 键 词：六氟化硫 氟氯烃 吹扫捕集 气相色谱 海水 

分 类 号：P714[天文地球—海洋科学] O657.63[理学—分析化学]