氮氧化物检测结果可靠性影响因素研究

Study on the Impact Factors to Result Reliability During Nitrogen Oxides Measurement

针对氮氧化物检测时分析方法及结果可能出现的问题进行了讨论,并对其可靠性进行了验证。以氮氧化物分析仪(化学发光原理)检测氮氧化物(NO_x)为例,分别对是否校准、定值标准的选择及不同工作模式3种情况下氮氧化物浓度测量结果的可靠性及影响因素进行评价,并用另外一种不同工作原理的傅里叶红外变换光谱法进行结果确认。结果表明:氮氧化物分析仪以自动模式进行工作时,不进行校准很可能得到完全错误的分析结果;浓度合适的标准物质的选择有利于提高分析结果的准确度。

The potential problems of analysis method and result during the measurement of nitrogen oxides(NO_x) were discussed with the verification of their reliability. A NO_x analyzer was selected to analyze the mole fraction of nitrogen oxides, three situations(1) calibration,(2) standard substance selection and(3) different analyzing modes were considered, the reliability of measurement results were evaluated with discussing the affecting factors. Furthermore, the final concentration values of the nitrogen oxides were confirmed again by FTIR spectroscopy, which is working with a different principle. It was concluded that calibration is necessary for auto working mode of NO_x analyzer, the incorrect results might be obtained without calibration. In addition, standard substance with appropriate concentration is beneficial for improving the accuracy of measurement results.