Reisen Fabienne, Aschmann Sara M, Atkinson Roger, Arey Janet
Air Pollution Research Center, University of California, Riverside, California 92521, USA.
Environ Sci Technol. 2005 Jun 15;39(12):4447-53. doi: 10.1021/es0483589.
Alkanes account for approximately 50% of nonmethane organic compounds present in urban atmospheres. Previous studies have shown that hydroxycarbonyls are important products ofthe OH radical initiated reactions of > or = C5 n-alkanes, but isomer-specific identifications and quantifications of these products have not been carried out. In this work, we have used solid-phase microextraction fibers precoated with O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine for on-fiber derivatization of carbonyl-containing compounds with subsequent analyses by combined gas chromatography-mass spectrometry (GC-MS) and GC with flame ionization detection (GC-FID). GC-MS analyses showed the presence of the oximes of 5-hydroxy-2-pentanone and 4-hydroxypentanal from the n-pentane reaction; 5-hydroxy-2-hexanone, 6-hydroxy-3-hexanone, and 4-hydroxyhexanal from the n-hexane reaction; 5-hydroxy-2-heptanone, 6-hydroxy-3-heptanone, 1-hydroxy-4-heptanone, and 4-hydroxyheptanal from the n-heptane reaction; and 5-hydroxy-2-octanone, 6-hydroxy-3-octanone, 7-hydroxy-4-octanone, and 4-hydroxyoctanal from the n-octane reaction. The formation yields of these 1,4-hydroxycarbonyls were determined from GC-FID analyses. By use of the yields of 1,4-hydroxycarbonyls formed from n-hexane, n-heptane, and n-octane at 50% relative humidity (and those from n-pentane at both 5 and 50% relative humidity), then formation of 1,4-hydroxycarbonyls accounts for 54% of the reaction products from n-pentane, 57% from n-hexane, 51% from n-heptane, and 53% from n-octane. Combined with previously measured yields of carbonyls, alkyl nitrates, and hydroxyalkyl nitrates, we can now accountfor approximately 74-118% of the products formed from the n-pentane through n-octane reactions.
烷烃约占城市大气中存在的非甲烷有机化合物的50%。先前的研究表明，羟基羰基化合物是≥C5正构烷烃的OH自由基引发反应的重要产物，但尚未对这些产物进行异构体特异性鉴定和定量。在本工作中，我们使用预涂有O-(2,3,4,5,6-五氟苄基)羟胺的固相微萃取纤维对含羰基化合物进行纤维上衍生化，随后通过气相色谱-质谱联用(GC-MS)和带有火焰离子化检测的气相色谱(GC-FID)进行分析。GC-MS分析表明，正戊烷反应生成了5-羟基-2-戊酮和4-羟基戊醛的肟；正己烷反应生成了5-羟基-2-己酮、6-羟基-3-己酮和4-羟基己醛；正庚烷反应生成了5-羟基-2-庚酮、6-羟基-3-庚酮、1-羟基-4-庚酮和4-羟基庚醛；正辛烷反应生成了5-羟基-2-辛酮、6-羟基-3-辛酮、7-羟基-4-辛酮和4-羟基辛醛。这些1,4-羟基羰基化合物的生成产率通过GC-FID分析确定。利用正己烷、正庚烷和正辛烷在50%相对湿度下（以及正戊烷在5%和50%相对湿度下）生成的1,4-羟基羰基化合物的产率，1,4-羟基羰基化合物的生成占正戊烷反应产物的54%、正己烷的57%、正庚烷的51%和正辛烷的53%。结合先前测得的羰基化合物、烷基硝酸盐和羟烷基硝酸盐的产率，我们现在可以解释正戊烷至正辛烷反应生成的产物的约7,4%-118%。
