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Environ Sci Technol

Title:		Synthesis of Four Monoterpene-Derived Organosulfates and Their Quantification in Atmospheric Aerosol Samples
Author(s):		Wang Y; Ren J; Huang XHH; Tong R; Yu JZ;
Address:		"Environmental Science Programs, section signInstitute of Environment, and double daggerDepartment of Chemistry, Hong Kong University of Science & Technology , Hong Kong, China"
Journal Title:		Environ Sci Technol
Year:		2017
Volume:		20170608
Issue:		12
Page Number:		6791 - 6801
DOI:		10.1021/acs.est.7b01179
ISSN/ISBN:		1520-5851 (Electronic) 0013-936X (Linking)
Abstract:		"Monoterpenes, a major class of biogenic volatile organic compounds, are known to produce oxidation products that further react with sulfate to form organosulfates. The accurate quantification of monoterpene-derived organosulfates (OSs) is necessary for quantifying this controllable aerosol source; however, it has been hampered by a lack of authentic standards. Here we report a unified synthesis strategy starting from the respective monoterpene through Upjohn dihydroxylation or Sharpless asymmetric dihydroxylation followed by monosulfation with the sulfur trioxide-pyridine complex. We demonstrate the successful synthesis of four monoterpene-derived OS compounds, including alpha-pinene OS, beta-pinene OS, limonene OS, and limonaketone OS. Quantification of OSs is commonly achieved using liquid chromatography-mass spectrometry (LC-MS) by either monitoring the [M-H](-) ion or through multiple reaction monitoring (MRM) of mass transitions between the [M-H](-) and m/z 97 ions. Comparison between the synthesized standards and previously adopted quantification surrogates reveals that camphor-10-sulfonic acid is a better quantification surrogate using [M-H](-) as the quantification ion, while the highly compound-specific nature of MRM quantification makes it difficult to choose a suitable surrogate. Both could be rationalized in accordance to their respective MS quantification mechanisms. The in-house availability of the authentic standards enables us to discover that beta-pinene OS, due to the sulfate group at the primary carbon, partially degrades to a dehydrogenated OS compound during LC/MS analysis and a hydroperoxy OS over a prolonged storage period (>5 month) and forms a regioisomer through intermolecular isomerization. Limonene OS was positively identified for the first time in ambient samples and found to be more abundant than alpha-/beta-pinene OS in the Pearl River Delta, China. This work highlights the critical importance of having authentic standards in advancing our understanding of the interactions between biogenic VOC emissions and anthropogenic sulfur pollution"
Keywords:		*Aerosols Bicyclic Monoterpenes Bridged Bicyclo Compounds China Environmental Monitoring *Monoterpenes;
Notes:		"MedlineWang, Yuchen Ren, Jingyun Huang, X H Hilda Tong, Rongbiao Yu, Jian Zhen eng 2017/05/27 Environ Sci Technol. 2017 Jun 20; 51(12):6791-6801. doi: 10.1021/acs.est.7b01179. Epub 2017 Jun 8"