离线采样法评估大气中 C3-C11 非甲烷烃。
Evaluation of offline sampling for atmospheric C3-C11 non-methane hydrocarbons.
机构信息
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Center for Excellence in Urban Atmospheric Environment, Institute of Regional Environment, Chinese Academy of Sciences, Xiamen 361021, China; University of Chinese Academy of Sciences, Beijing 100049, China.
出版信息
J Environ Sci (China). 2022 Mar;113:132-140. doi: 10.1016/j.jes.2021.05.022. Epub 2021 Jun 23.
The concentration variation of C3-C11 non-methane hydrocarbons (NMHCs) collected in several types of commercial flexible bags and adsorption tubes was systematically investigated using a gas chromatography-flame ionization detector (GC-FID) system. The percentage loss of each NMHC in the polyvinyl fluoride (PVF) bags was less than 5% during a 7-hr storage period; significant NMHCs loss was detected in aluminum foil composite film and fluorinated ethylene propylene bags. The thermal desorption efficiency of NMHCs for adsorption tubes filled Carbopack B and Carboxen1000 sorbents was greater than 95% at 300℃, and the loss of NMHCs in the adsorption tubes during 20-days storage at 4℃ was less than 8%. The thermal desorption efficiency for C11 NMHCs in the adsorption tube filled with Carbograph 1 and Carbosieve SⅢ absorbents was less than 40% at 300℃, and pyrolysis of the absorbents at 330℃ interfered significantly with the measurements of some alkenes. The loss of alkenes was significant when NMHCs were sampled by cryo-enrichment at -90℃ in the presence of O for the online NMHC measurements, and negligible for enrichment using adsorption tubes at 25℃. Although O scrubbers have been widely used to eliminate the influence of O on NMHC measurements, the loss of NMHCs with carbon numbers greater than 8 was more than 10%. Therefore, PVF bags and adsorption tubes filled Carbopack B and Carboxen1000 sorbents were recommended for the sampling of atmospheric NMHCs.
采用气相色谱-火焰离子化检测器（GC-FID）系统，系统研究了几种商用软袋和吸附管中采集的 C3-C11 非甲烷烃（NMHC）的浓度变化。在 7 小时的储存期内，聚偏氟乙烯（PVF）袋中每种 NMHC 的损失百分比小于 5%；在铝箔复合膜和氟化乙烯丙烯袋中检测到明显的 NMHC 损失。在 300℃时，装有 Carbopack B 和 Carboxen1000 吸附剂的吸附管中 NMHC 的热解吸效率大于 95%，在 4℃下储存 20 天时吸附管中 NMHC 的损失小于 8%。在 300℃时，装有 Carbograph 1 和 Carbosieve SⅢ吸附剂的吸附管中 C11 NMHC 的热解吸效率小于 40%，在 330℃时吸附剂的热解会对一些烯烃的测量产生显著干扰。当在存在 O 的情况下，NMHC 在线 NMHC 测量时在-90℃下进行冷冻浓缩采样时，烯烃的损失是显著的，而在 25℃下使用吸附管富集时损失可以忽略不计。尽管 O 洗涤器已被广泛用于消除 O 对 NMHC 测量的影响，但碳数大于 8 的 NMHC 损失超过 10%。因此，建议使用 PVF 袋和装有 Carbopack B 和 Carboxen1000 吸附剂的吸附管来采集大气 NMHC。
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