摘要
介绍了氮气中三氯一氟甲烷、二氯二氟甲烷、1,1,2-三氯-1,2,2-三氟乙烷、一氯三氟甲烷4种氟氯烃混合标准气体的制备方法和定值方法。考察标准气体在气瓶内壁的吸附作用、制备重现性、均匀性和稳定性。浓度水平为5-9μmol/mol的4种氟氯烃混合标准气体采用称量法制备,采用气相色谱法测定。经瓶内均匀性考察,瓶内均匀性良好。经时间稳定性考察显示,4种氟氯烃混合标准气体使用有效期为1年。标准气体的不确定度包含样品定值不确定度、瓶内不均匀性和不稳定引起的不确定度,经评估和计算,其扩展相对不确定度为3%（置信度为95%）。4种氟氯烃混合标准气体可以为温室气体环境监测提供标准技术支持。
The results of the development and determination of hydrochlorofluorocarbons containing 4 compounds such as trichlo- rofluoromethane, dichlorodifluoromethane, 1 , 1 , 2-trichloro-1 , 2,2-trifluoroethanc, chlorotrifluoromethane in nitrogen gas standards are investigated. Cylinder selection, preparation method, with-in bottle homogeneity and stability researches for the gas standard mixtures were performed. Four kinds of hydrochlorofluorocarbons gas standard mixture at 5 - 9 μmol/mol was prepared by gravimetric method. This set of primary standards was intercompared to the existing gas cylinder standards using gas chromatography with a hydrogen flame ionization detector. The linear regression analysis showed excellent agreement among the standards for each compound. As a result of with-in homogeneity,the data showed that the 4 compounds were homogeneous in the cylinder. The long- term stability of the gas standard is associated with the behavior of the gas standard at the shelves of the producer. All four hydro- chlorofluorocarbons in gas cylinders have been evaluated over time and have shown stability for as long as 12 months. The uncer- tainty for the certified values of each analyte in the gas standards included uncertainty of the certified value,uncertainty of inho- mogeneity and instability. The results showed the expanded uncertainty was 3% at the 95% confidence interval per compound. This work supplied the standards support for the determination of greenhouse gas in ambient air.
出处
《化学试剂》
CAS
北大核心
2016年第9期887-889,920,共4页
Chemical Reagents
基金
环保公益性科研专项项目(201309013)
关键词
氟氯烃
标准气体
均匀性
稳定性
不确定度
hydrochloroiluorocarbon
gas standard
homogeneity
stability
uncertainty
