FTIR和光谱差减法的大气质量检测  

Air Quality Detecting Based on FTIR and Spectrum Substraction

作　　者：汪曣[1] 张艳超[1] 李宁[1] 赵学玒[1] 

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072

出　　处：《光电工程》2008年第11期73-76,81,共5页Opto-Electronic Engineering

摘　　要：针对大气质量检测的多组分定量分析,本文提出利用傅里叶变换红外光谱(FTIR)技术与光谱差减相结合的气体定量方法。该方法是根据迈克尔逊干涉原理与朗伯-比尔定律,采用怀特型长光程气体池与FTIR光谱仪相结合的方式来测得痕量气体的红外光谱,最后利用光谱差减法反演出气体浓度。为了避免背景环境的干扰(主要是避免水和CO2吸收峰的干扰),选择了在某些特殊波段内的待测气体吸收峰进行分析。本文分别对CO,SO2,NO2,NO和CO2气体进行了定量分析,相应的最佳观测波段依次为:2250～2020cm-1,1230～1070cm-1,2940～2840cm-1,1965～1775cm-1,668.24cm-1。实验结果表明,经浓度反演相对误差可达到10%以内。To realize multi-component analysis of air quality detecting, an gas quantitative method combining technique of Fourier Transform Infrared （FTIR） spectroscopy and the method of spectrum subtraction was applied. Based on Michelson micro-interference principle and Lambert-Beer law, FTIR spectrometer coupled with long path White gas cell was used to measure the infrared spectrums of the trace gases, and then, the values of gas concentration was deduced by the method of spectrum subtraction. Furthermore, for the gases to be detected, the regions were chosen carefully to provide optimum detection of the compounds interested with minimum interference by other compounds （especially, vapor and CO2）. The optimal window for CO, SO2, NO2 , NO and CO2 would be the regions at 2250-2020 cm^-1, 1230-1070 cm^-1, 2 940-2 840 cm^-1, 1 965-1 775 cm^-1, and around 668.24 cm^-1 respectively. The quantitative analysis for CO, SO2, NO2, NO and CO2 of different concentrations was carried out in this way. Results indicate that the values of relative errors are below 10%.

关 键 词：大气污染物 傅里叶变换红外光谱 长光程池 浓度光程积 光谱差减 

分 类 号：O657.33[理学—分析化学]