氮中甲烷气体标准物质的研制

Preparation of reference material of methane in nitrogen

以甲烷纯度标准物质和高纯氮气为原料,采用称重法制备氮中甲烷气体标准物质。称量过程考虑了空气密度、天平线性系数、气瓶体积膨胀系数、转移和装卸过程产生的质量损失等因素。用气相色谱仪测定了高纯氮气中甲烷的含量,并对研制的标准物质进行了压力均匀性和时间稳定性检验。结果表明,研制的氮中甲烷气体标准物质标准值为10.0~1.00×10~3μmol/mol(U_(rel)=2%,k=2),该标准物质具备良好的均匀性和稳定性,可用于测量仪器的校准、测量过程的质量控制及分析方法的确认和评价。

The reference material of methane in nitrogen was prepared by using methane purity standard material and nitrogen. The air density, the linear coefficient of the balance, the volume expansion coefficient of the cylinder, the mass wear and tear caused by the transfer and the loading and unloading process was considered in the weighing process. The content of methane in high purity nitrogen was measured by gas chromatograph, and the pressure uniformity and time stability were tested for the standard substances prepared. The results show that the standard value of the reference material of methane in nitrogen was 10.0-1.00×103μmol/mol （Urel=2%, k=2）. The reference material can be used for calibration of instrument, quality control of measurement, and confirmation and evaluation of analysis method.