A VUV photoionization mass spectrometric study on the OH-initiated photooxidation of isoprene with synchrotron radiation

• Published in: Journal of environmental sciences (China) 2012-01, Vol.24 (12), p.2075-2082
• Main Authors: Pan, Gang, Hu, Changjin, Huang, Mingqiang, Wang, Zhenya, Cheng, Yue, Liu, Zhi, Gu, Xuejun, Zhao, Weixiong, Zhang, Weijun, Chen, Jun, Liu, Fuyi, Shan, Xiaobin, Sheng, Liusi
• Format: Article
• Language: English
• Subjects: acetic acid; acetone; Butadienes - chemistry; Butadienes - radiation effects; chemical composition; energy; formaldehyde; formic acid; Hemiterpenes - chemistry; Hemiterpenes - radiation effects; isoprene; Mass Spectrometry; Oxidation-Reduction; Pentanes - chemistry; Pentanes - radiation effects; photooxidation; reaction mechanisms; smog chamber; synchrotron radiation; Synchrotrons; volatile organic compounds; VUV photoionization mass spectrometry; 光氧化反应; 光电离质谱; 同步加速器辐射; 同步辐射; 异戊二烯; 挥发性有机化合物; 气态产物; 真空紫外
• ISSN: 1001-0742; 1878-7320
• DOI: 10.1016/S1001-0742(11)61051-6

The gas-phase organic compounds resulting from OH-initiated photooxidation of isoprene have been investigated on-line by VUV photoionization mass spectrometry based on synchrotron radiation for the first time. The photoionization efficiency curves of the corresponding gaseous products as well as the chosen standards have been deduced by gating the interested peaks in the photoionization mass spectra while scanning the photon energy simultaneously, which permits the identification of the pivotal gaseous products of the photooxidation of isoprene, such as formaldehyde (10.84 eV), formic acid (11.38 eV), acetone (9.68 eV), glyoxal (9.84 eV), acetic acid (10.75 eV), methacrolein (9.91 eV), and methyl vinyl ketone (9.66 eV). Proposed reaction mechanisms leading to the formation of these key products were discussed, which were completely consistent with the previous works of different groups. The capability of synchrotron radiation photoionization mass spectrometry to directly identify the chemical composition of the gaseous products in a simulation chamber has been demonstrated, and its potential application in related studies of atmospheric oxidation of ambient volatile organic compounds is anticipated.