大气甲醛在线分析仪的设计与应用

The design and application of an online gaseous formaldehyde analyzer

基于Hantzsch荧光法设计了一套大气甲醛在线分析仪,通过优化测量参数,发现该仪器可长期稳定运行,其时间分辨率为120 s,检出限为84×10-12(体积分数,下同)(S/N=6),在84×10-12~39.2×10-9的甲醛测量范围内,标线可决系数R2=0.9996.同时,对该仪器与商品化仪器AL4021进行了长期外场比对实验,结果发现,两者测量结果的一致性较好,R2=0.963,表明其适用于环境大气甲醛浓度的在线监测.外场观测结果表明,德州站点冬季甲醛浓度范围为0.6×10-9~21.6×10-9,均值为2.9×10-9,且其日变化显著.

An online gaseous formaldehyde analyzer has been developed based on Hantzsch fluorescence technique. Under optimized instrumental settings,the instrument is shown to be running stably for long time period. Gaseous formaldehyde can be detected with good linearity（ R2= 0. 9996） over concentrations ranging from 84×10^-12 to 39.2×10^-9. The time resolution and the limit of detection is determined to be 120 s and 84×10^-12,respectively.The newly developed formaldehyde analyzer was running in parallel with a commercial instrument based on the same technique（ AL4021,Aero Laser Gmb H） during a field observation campaign. The measured formaldehyde concentration in the atmosphere ranges from 0.6 × 10-9 to 21.6 × 10-9,with an average value of 2.9×10^-9. Clear diurnal variation pattern was observed. Good agreement is found for the formaldehyde concentrations measured by both instruments（ R2= 0.963）.