The Development of a Continuous Real-time Measuring System for Atmospheri Ammonia

本文介绍了一种大气中痕量氨的连续实时测量系统，该系统的分析过程如下：1）空气样品由装有5%KOH涂层的Porasil B收集管收集; 2)样品气用居里点裂解器在315 ℃下快速加热进行热解吸，并将组分转移到气相色谱柱上。3)采用气相色谱-傅里叶变换红外光谱法（GC-FTD）分析，以15%PEG600 - 5%KOH玻璃柱为填充剂，氦气与1%甲烷混合为载气，室温下收集管的收集容量约为4L，流速为200 ml/min。在1 ~ 4 min的解吸时间内，回收率接近100%，检测限为3 pg，可在2L进样量下测定2 ppt的氨。

A continuous real-time measuring system f or trace leve s of ammonia in the atmosphere has been developed.The analytical procedures by this system are performed with the following process : 1)Air sample is collected by the collection tube packed with 5 % KOH coated Porasil B. 2)The thermal desorption of the sample gas is was performed by heatingrapidly at 315 ﾟC with a curie-point pyrolyzer and the components are transfered to GC column. 3)the components are analyzed by GC-FTD.Gaschromatgraphic separation was performed with a glass colmn packed with 15 % PEG 600-5 % KOH and helium carrier gas mixed with 1 % methane was used.The collection capacity of the collection tube was about 4 l with a flow rate of 200 ml/min at ambient temperature. The recovery effeciencies from the collection tube were almost 100 % under the 1 - 4 min desorption time.Detection limit of this system was 3 pg, which allowed to determine 2 ppt of ammonia with sampling volume of 2 l.