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Li L, Chao B, Wang W, Luo Y, Wang L, Lin L, Yang G, Wu J. Identification and quantification of IEPOX in ambient aerosols, using electron and chemical ionization sources GC/MS as their trimethylsilyl ethers, and using H-NMR. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 872:162186. [PMID: 36791868 DOI: 10.1016/j.scitotenv.2023.162186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Isoprene is the most abundant non-methane hydrocarbon (NMHC) emitted by vegetation, and the precursor that makes the greatest contribution to secondary organic aerosols (SOA) in the troposphere. Atmospheric oxidation of isoprene produces a series of reactive intermediates, isoprene epoxydiols (IEPOX). The reactive uptake of IEPOX is the significant formation pathway of atmospheric SOA. In this work, four isomers of IEPOX were synthesized, derivatized by silylation reagents, and measured by gas chromatography/mass spectrometry (GC/MS). The electron-impact (EI) and methane chemical ionization (CI) sources mass spectra of trimethylsilyl ester (TMS) derivatives of IEPOX isomers were obtained and the fragmentation behaviors of the derivatives were examined. Moreover, the hydrogen nuclear magnetic resonance (H-NMR) spectra of IEPOX isomers were also obtained and the peak intensities in the H-NMR spectra were analyzed. Based on the standard spectra, IEPOX isomers were identified in ambient PM2.5 aerosols in the Gongga Mountain (China). The peak sequence of TMS derivatives of IEPOX isomers in GC/MS chromatogram was δ4-IEPOX, δ1-IEPOX, cis-β-IEPOX and trans-β-IEPOX. The isomers with the highest concentrations were δ1-IEPOX (threo- and erythro-). The mass ratios of IEPOX to 2-methyltetrols were 0.02-6.0 and the concentrations of IEPOX were 0.8-41.6 ng/m3 in the PM2.5 aerosols. The current study verified the core roles of IEPOX as active intermediates in photo oxidation of isoprene in ambient atmosphere.
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Affiliation(s)
- Li Li
- Rural Environment Protection Engineering & Technology Center of Sichuan Province, College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China.
| | - Biao Chao
- Rural Environment Protection Engineering & Technology Center of Sichuan Province, College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
| | - Wu Wang
- Institute of Environmental Pollution and Health, Shanghai University, Shanghai 200444, China
| | - Yina Luo
- Rural Environment Protection Engineering & Technology Center of Sichuan Province, College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
| | - Lilin Wang
- Rural Environment Protection Engineering & Technology Center of Sichuan Province, College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
| | - Lili Lin
- Rural Environment Protection Engineering & Technology Center of Sichuan Province, College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
| | - Gang Yang
- Rural Environment Protection Engineering & Technology Center of Sichuan Province, College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
| | - Jun Wu
- Rural Environment Protection Engineering & Technology Center of Sichuan Province, College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China
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Liang L, Engling G, Xu W, Ma Q, Lin W, Liu X, Liu C, Zhang G. Observational insights into the compound environmental effect for 2-methyltetrols formation under humid ambient conditions. CHEMOSPHERE 2022; 289:133153. [PMID: 34875293 DOI: 10.1016/j.chemosphere.2021.133153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 11/26/2021] [Accepted: 12/02/2021] [Indexed: 06/13/2023]
Abstract
Laboratory experiments suggest acid-catalyzed aqueous-phase production can promote the formation of isoprene SOA, i.e., 2-methyltetrols. In this study we use ambient observations of the 2-methyltetrols along with other chemical measurements, as well as meteorological factors to investigate the relative importance of environmental influence for isoprene epoxydiols (IEPOX) SOA formation under atmospheric humidity conditions. The 2-Methyltetrols revealed good relationships with temperature and total solar radiation, but were weakly correlated with aerosol acidity and SO42-. EC-scaled 2-methyltetrols were observed to vary in a narrow pH range (1.5-2.0), indicating aerosol acidity was not a limiting factor for 2-methyltetrols formation. High values of 2-methyltetrols were consistently observed at high total solar radiation, the strong dependence of total solar radiation demonstrated that photochemical processes dominated 2-methyltetrols formation in humid environments. Although 2-methyltetrols can be enhanced by acid-catalyzed aqueous-phase reactions, it is not sufficient to compensate the synchronously weakened photochemical activity influence, leading to an obvious net decrease in the formation of 2-methyltetrols in the ambient. Moreover, aerosol droplet acidity was reduced under high liquid water content (LWC) condition, subsequently diminishing the enhancement of SOA formation by acidity. Overall, our results highlight that the environmental impact factors are highly variable and interplay, influencing the production of 2-methyltetrols, and suggest that the formation pathway of 2-methyltetrols is insensitive to aerosol acidity but dominated by photochemical production process in humid environments.
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Affiliation(s)
- Linlin Liang
- State Key Laboratory of Severe Weather & Key Laboratory for Atmospheric Chemistry, Chinese Academy of Meteorological Sciences, Beijing, 100081, China.
| | - Guenter Engling
- Division of Atmospheric Sciences, Desert Research Institute, Reno, NV, USA; Now at: California Air Resources Board, El Monte, CA, 91731, USA
| | - Wanyun Xu
- State Key Laboratory of Severe Weather & Key Laboratory for Atmospheric Chemistry, Chinese Academy of Meteorological Sciences, Beijing, 100081, China
| | - Qianli Ma
- Lin'an Regional Atmosphere Background Station, Lin'an, 311300, China
| | - Weili Lin
- College of Life and Environmental Sciences, Minzu University of China, Beijing, 100081, China
| | - Xuyan Liu
- National Satellite Meteorological Center, China Meteorological Administration, Beijing, 100081, China
| | - Chang Liu
- State Key Laboratory of Severe Weather & Key Laboratory for Atmospheric Chemistry, Chinese Academy of Meteorological Sciences, Beijing, 100081, China
| | - Gen Zhang
- State Key Laboratory of Severe Weather & Key Laboratory for Atmospheric Chemistry, Chinese Academy of Meteorological Sciences, Beijing, 100081, China
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Xu S, Zhao C, Deng X, Zhang R, Qu L, Wang M, Ren S, Wu H, Yue Z, Niu B. Multivariate analysis for organic milk authentication. J Chromatogr B Analyt Technol Biomed Life Sci 2021; 1186:123029. [PMID: 34798418 DOI: 10.1016/j.jchromb.2021.123029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Revised: 10/12/2021] [Accepted: 11/06/2021] [Indexed: 11/15/2022]
Abstract
To differentiate organic milk (OM) from conventional milk (CM), an orthogonal projection to latent structure-discriminant analysis (OPLS-DA) model was constructed using δ13C, δ15N, δ18O, 51 elements and 35 fatty acids (FAs) as the variables. So far, most reported studies barely use three or more types of variables, but more variables could avoid one-sidedness and get stabler models. Our multivariate model combines geographical and nutritional parameters and displays better explanatory and predictive abilities (R2X = 0.647, R2Y = 0.962 and Q2 = 0.821) than models based on fewer variables for differentiating OM and CM. In particular, δ15N, Se, δ13C, Eu, K and α-Linolenic acid (ALA) are found to be critical parameters for the discrimination of OM. These results show that the multivariate model based on stable isotopes, elements and FAs can be used to identify OM, and can potentially expand the global databases for quality and authenticity of milk.
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Affiliation(s)
- Siyan Xu
- School of Life Sciences, Shanghai University, Shanghai 200444, China; Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China
| | - Chaomin Zhao
- Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China.
| | - Xiaojun Deng
- Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China
| | - Runhe Zhang
- Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China
| | - Li Qu
- Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China
| | - Min Wang
- Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China
| | - Shuo Ren
- Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Customs, Shanghai 200135, China
| | - Hao Wu
- Food Inspection and Quarantine Center, Shenzhen Customs, Shenzhen 518000, China
| | - Zhenfeng Yue
- Food Inspection and Quarantine Center, Shenzhen Customs, Shenzhen 518000, China
| | - Bing Niu
- School of Life Sciences, Shanghai University, Shanghai 200444, China
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Zhang J, Chen L, Hou X, Lin M, Ren X, Li J, Zhang M, Zheng X. Multi-isotopes and hydrochemistry combined to reveal the major factors affecting Carboniferous groundwater evolution in the Huaibei coalfield, North China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 791:148420. [PMID: 34412374 DOI: 10.1016/j.scitotenv.2021.148420] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
Both natural processes and anthropogenic activities have significant effects on groundwater evolution in coal mining regions. In this study, the primary controlling mechanism of the groundwater chemistry evolution for the Carboniferous groundwater in the Huaibei coalfield, North China was proposed based on the hydrogeochemical indicators combining with multiple isotope tracers. The diversity of hydrochemical types indicates the complexity of the hydrogeochemical environment in the groundwater, which is recharged by precipitation infiltration with minimal evaporation according to the distributions of δD and δ18O. Additionally, ion correlation analysis suggests that minerals dissolution and cation exchange between Na+ and Ca2+ are the dominant processes within that groundwater. The hydrochemical and δ13CDIC characteristics of the groundwater demonstrate that HCO3- is mainly controlled by the dissolution of carbonate minerals and soil CO2, and the proportion of the latter is believed to be dominated by the hydrogeologic conditions. Similarly, the values of SO42- and δ34SSO4 indicate that a small portion of SO42- in the groundwater in the northern part originates from the meteoric precipitation, while it is mainly derived from the dissolution of gypsum in the southern part. Furthermore, mining activities also alter the groundwater level and flow conditions through pumping and drainage, which enhances the interaction between groundwater and aquifer lithologies, thereby affects the hydrogeochemical processes. The findings of this work are of great significance for promoting the safe exploitation of deep coal resources and the sustainable utilization of groundwater in the Huaibei coalfield, as well as the most of other coalfields in North China.
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Affiliation(s)
- Jie Zhang
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Luwang Chen
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Xiaowei Hou
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Manli Lin
- School of Resources and Civil Engineering, Suzhou University, Suzhou 234000, China
| | - Xingxing Ren
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jun Li
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
| | - Miao Zhang
- School of Earth and Environment, Anhui University of Science and Technology, Huainan 232001, China
| | - Xin Zheng
- School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
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