氮中低含量一氧化碳气体标准物质的定值方法

Determination Method for Low Content Carbon Monoxide Gas Standard Substance in Nitrogen

选择空气分离法制备氮气时,高纯氮气中不可避免会含有微量的一氧化碳。如果选择高纯氮作为稀释气体制作一氧化碳标准物质,将会使最终定值结果存在较大误差。本文介绍了一种基于气象色谱仪的氮中低含量一氧化碳标准物质定值方法,具有灵敏度和精密度高、分析速度快等特点。文章首先概述了标准物质的制备方法,随后从原料气体的纯度分析、高纯气体的选择等方面,总结了氮中低含量一氧化碳气体标准物质的定值流程。最后选择氢火焰甲烷转化法和气相色谱脉冲放电氦离子化检测器,分析了低含量一氧化碳的定值方法。测试结果表明,配制的气体标准物质与中国计量科学研究院研制的气体标准物质的量值在不确定范围内吻合,定值方法科学有效。

When the air separation method is selected to prepare nitrogen,the high-purity nitrogen will inevitably contain trace amounts of carbon monoxide.If high-purity nitrogen is selected as the diluent gas to make the carbon monoxide standard material,there will be a large error in the final determination result.In this paper,a gas chromatography-based method for the determination of low-content carbon monoxide standard substances in nitrogen is introduced,which has the characteristics of high sensitivity,high precision,and fast analysis speed.The article firstly outlines the preparation method of the reference material,and then summarizes the process of determining the value of the reference material for low-content carbon monoxide gas in nitrogen from the aspects of the purity analysis of the raw gas and the selection of high-purity gas.Finally,the hydrogen flame methane conversion method and the gas chromatography pulse discharge helium ionization detector were selected to analyze the determination method of low content carbon monoxide.The test results show that the prepared gas reference material is consistent with the gas reference material developed by the China Institute of Metrology within the uncertainty range,and the determination method is scientific and effective.