一氧化氮标准气体中二氧化氮杂质FTIR定量方法研究及标气质量分析

Measurement of Nitrogen Dioxide Impurity in Nitrogen Monoxide Standard Gas by FTIR with Discussion on the Influence Factors to the Mixture Quality

一氧化氮标准气体在我国空气质量监测工作中广泛用于氮氧化物分析仪的校准,标准气体的质量对环境空气中氮氧化物的测量结果也有着显著的影响。利用傅里叶变换红外光谱仪建立了一套精确测量低浓度二氧化氮方法,并对一氧化氮标准气体产品中二氧化氮杂质进行了测量。结果显示有少部分样品中存在较高浓度的二氧化氮杂质。进一步讨论了可能导致一氧化氮标准气体中二氧化氮杂质偏高的原因,及此种情况对化学发光法氮氧化物分析仪准确测量空气中氮氧化物可能产生的影响。为了准确校准化学发光法氮氧化物分析仪,应关注一氧化氮标准气体产品中的二氧化氮杂质的含量。

Standard gas of nitrogen monoxide is widely used in the field of domestic air quality monitoring for the calibration of nitrogen oxides monitor,thus the quality of standard gas will give great effect on the measurement results of nitrogen oxides in air.In this paper,a FTIR system for the accurate measurement of low concentration NO_(2) was developed and used to measure the impurity of NO_(2) in some nitrogen monoxide standard gases.Results showed there were high concentration of NO_(2) impurity in some samples.This paper also discussed the possible reasons,which could lead to high level NO_(2) impurity,and the effects of these phenomena on the accurate measurement of nitrogen oxides in air by the chemiluminescent nitrogen oxides analyzer.It s proposed that attention should be paid to the content of nitrogen dioxide impurity in the standard gas products of nitrogen monoxide in order to calibrate chemiluminescent analyzer accurately.