环境监测用正丁烷气体标准样品的研制

Development of n-Butane Gas Standard for Environmental Monitoring

采用称量法制备了氮气中正丁烷气体标准样品,其含量为1μmol/mol。建立了使用气相色谱-氢火焰离子检测器(GC-FID)分析氮气中正丁烷气体标准样品的方法。此外,考察了制备方法和分析方法的可靠性,还对氮气中正丁烷气体标准样品随使用压力和时间的量值变化等性质进行了测定。最后,对气体标准样品的不确定度进行了评估。结果显示,浓度水平为1μmol/mol的氮气中正丁烷气体标准样品的最低使用压力为1 MPa,有效期为18个月,其相对扩展不确定度为2%。

The n-butane with concentration of 1 μmol/mol in nitrogen was prepared using a four-step weighing method.The analytical method of this gas standard was established using GC-FID and the repeatability of the preparation method and analytical method were also examined.In addition,the homogeneous and stable were performed which indicated this gas standard was homogeneous above to 1 MPa in cylinders and remained stable no less than 18 months.Finally,the expanded uncertainty of the n-butane with concentration of 1 μmol/mol in nitrogen was calculated as 2%.