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

研制了一种大气中痕量氨连续实时测量系统。该系统的分析过程如下：1)空气样品由装有5% KOH包覆的Porasil b的收集管收集；2)样品气体在315°C的温度下用居里点热解装置热解吸，组分转移到气相色谱柱上。3)用GC-FTD对各组分进行分析。气相色谱分离采用15% peg600 - 5% KOH填充的玻璃柱，氦气载气与1%甲烷混合。在常温下，收集管的收集量约为4 l，流速为200 ml/min。在1 ~ 4 min的脱附时间内，收集管的回收率接近100%。该系统的检出限为3pg，以2l的进样量，可检出2ppt的氨气。

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.