甲醇标准气体的研制及定值结果的不确定度评定

Uncertainty Evaluation of Characterization on Reference Material of Methanol in Nitrogen

重量法制备了浓度水平为8μmol/mol的甲醇标准气体。通过甲醇原料中水分及蒸发残渣分析,并根据归一化法采用气相色谱仪(GC-FID)对甲醇的纯度进行定值。采用注射法配制氮气中甲醇标准气体,考察了制备方法的重复性。并对标准气体进行了均匀性与稳定性分析、比对研究,对甲醇标准气体进行了量值不确定度评定。浓度水平为8μmol/mol的甲醇标准气体扩展不确定度为1.8%,能够满足环境甲醇气体监测分析的要求。

Characterization and uncertainty evaluation on reference material of methanol in nitrogen prepared with gravimetric method is investigated.The purity of the raw material of methanol was determined by normalization method with gas chromatography equipped with fire ionization detector（GC/FID）,and the content of water and evaporation residue have been measured.Reference material of methanol in nitrogen was prepared by syringe method.The reproducibility of the preparing method,homogeneity and stability of methanol standard gas were investigated.The uncertainties caused in the whole producing processes of the reference material were analyzed and evaluated.The expanded relative uncertainty is 1.8% at the concentration of 8 μmol/mol for methanol standard gas.The methanol standard gas was intended for use in environment methanol monitoring.