【摘 要】
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The concentration variation of C3-C11 non-methane hydrocarbons (NMHCs) collected in several types of commercial flexible bags and adsorption tubes was systematically inves-tigated using a gas chromatography-flame ionization detector (GC-FID) system.The pe
【机 构】
：
Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;Univ
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The concentration variation of C3-C11 non-methane hydrocarbons (NMHCs) collected in several types of commercial flexible bags and adsorption tubes was systematically inves-tigated using a gas chromatography-flame ionization detector (GC-FID) system.The per-centage 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°c,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 O3 for the online NMHC measurements,and negligible for enrichment us-ing adsorption tubes at 25℃.Although O3 scrubbers have been widely used to eliminate the influence of O3 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.
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