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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 effects of four kinds of chlorofluorocarbon mixed standard gases, such as trichloromonofluoromethane, dichlorodifluoromethane, 1,1,2-trichloro-1,2,2-trifluoroethane and chlorotrifluoromethane, in nitrogen Preparation and valuation methods. Investigate the standard gas adsorption in the cylinder wall, preparation of reproducibility, uniformity and stability. Four HCFC mixed standard gases with concentration levels of 5 ~ 9μmol / mol were prepared by weighing method and determined by gas chromatography. Uniformity of the bottle inspected, the bottle of good uniformity. The investigation of stability over time shows that the four HCFC mixed standard gases are valid for one year. The uncertainty of the standard gas includes the uncertainties caused by the uncertainty of the sample set, in-bottle non-uniformity and instability. The relative uncertainty of expansion is 3% (confidence 95%) after evaluation and calculation. Four HCFC mixed standard gases provide standard technical support for greenhouse gas environmental monitoring.