scholarly journals Multidimensional Analytical Characterization of Water-Soluble Organic Aerosols: Challenges and New Perspectives

2021 ◽  
Vol 11 (6) ◽  
pp. 2539
Author(s):  
Regina M. B. O. Duarte ◽  
João T. V. Matos ◽  
Armando C. Duarte
Keyword(s):  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
Organic Aerosols ◽  
Analytical Techniques ◽  
Water Soluble ◽  
Chemical Complexity ◽  
Molecular Features ◽  
High Resolution Mass ◽  
Analytical Strategies ◽  
Resolution Mass

Water-soluble organic aerosols (OA) are an important component of air particles and one of the key drivers that impact both climate and human health. Understanding the processes involving water-soluble OA depends on how well the chemical composition of this aerosol component is decoded. Yet, obtaining detailed information faces several challenges, including water-soluble OA collection, extraction, and chemical complexity. This review highlights the multidimensional non-targeted analytical strategies that have been developed and employed for providing new insights into the structural and molecular features of water-soluble organic components present in air particles. First, the most prominent high-resolution mass spectrometric methods for near real-time measurements of water-soluble OA and their limitations are discussed. Afterward, a special emphasis is given to the degree of compositional information provided by offline multidimensional analytical techniques, namely excitation–emission (EEM) fluorescence spectroscopy, high-resolution mass spectrometry and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and their hyphenation with chromatographic systems. The major challenges ahead on the application of these multidimensional analytical strategies for OA research are also addressed so that they can be used advantageously in future studies.

Seasonal differences of urban organic aerosol composition – an ultra-high resolution mass spectrometry study

2012 ◽  
Vol 9 (3) ◽  
pp. 298 ◽  
Author(s):  
Angela G. Rincón ◽  
Ana I. Calvo ◽  
Mathias Dietzel ◽  
Markus Kalberer
Keyword(s):  
Mass Spectrometry ◽  
Chemical Composition ◽  
High Resolution ◽  
Elemental Composition ◽  
High Resolution Mass Spectrometry ◽  
Organic Aerosols ◽  
Urban Site ◽  
High Resolution Mass ◽  
Oxidised Nitrogen ◽  
Resolution Mass

Environmental contextUnderstanding the molecular composition and chemical transformations of organic aerosols during atmospheric aging is a major challenge in atmospheric chemistry. Ultra-high resolution mass spectrometry can provide detailed information on the molecular composition of organic aerosols. Aerosol samples collected in summer and winter at an urban site are characterised and compared in detail with respect to the elemental composition of their components, especially nitrogen- and sulfur-containing compounds, and are discussed with respect to atmospheric formation processes. AbstractOrganic compounds are major constituents of atmospheric aerosol particles. The understanding of their chemical composition, their properties and reactivity are important for assessing aerosol effects upon both global climate change and human health. The composition of organic aerosols is poorly understood, mainly due to its highly complex chemical composition of several thousand compounds. There is currently no analytical technique available covering a wide enough chemical space to characterise this large number of organic compounds. In recent years ultra-high resolution mass spectrometry has been increasingly used to explore the chemical complexity in organic aerosols from laboratory and ambient samples. In the present study ambient particles <1 µm were collected at an urban site in Cambridge, UK, from August to December 2009. The water-soluble organic fraction of the filters was separated from inorganic ions following a procedure developed for humic-like substance isolation. Ultra-high resolution mass spectrometry analyses were performed in negative and positive polarity. Data in the mass range of m/z 50–350 were analysed for their elemental composition. Summer samples generally contained more components than winter samples. The large number of compounds was subdivided into groups according to their elemental composition. Up to 80 % of the peaks contain nitrogen and sulfur functional groups and only ~20 % of the compounds contain only C, H and O atoms. In summer the fraction of compounds with oxidised nitrogen and sulfur groups increases compared with winter indicating a photo-chemical formation route of these multifunctional compounds. In addition to oxidised nitrogen compounds a large number of amines was identified.

scholarly journals Molecular composition of particulate matter emissions from dung and brushwood burning household cookstoves in Haryana, India

2018 ◽  
Vol 18 (4) ◽  
pp. 2461-2480 ◽  
Author(s):  
Lauren T. Fleming ◽  
Peng Lin ◽  
Alexander Laskin ◽  
Julia Laskin ◽  
Robert Weltman ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Particulate Matter ◽  
High Resolution ◽  
Biomass Burning ◽  
High Resolution Mass Spectrometry ◽  
Geometric Mean ◽  
Organic Aerosols ◽  
Molecular Composition ◽  
High Resolution Mass ◽  
Resolution Mass

Abstract. Emissions of airborne particles from biomass burning are a significant source of black carbon (BC) and brown carbon (BrC) in rural areas of developing countries where biomass is the predominant energy source for cooking and heating. This study explores the molecular composition of organic aerosols from household cooking emissions with a focus on identifying fuel-specific compounds and BrC chromophores. Traditional meals were prepared by a local cook with dung and brushwood-fueled cookstoves in a village in Palwal district, Haryana, India. Cooking was done in a village kitchen while controlling for variables including stove type, fuel moisture, and meal. Fine particulate matter (PM2.5) emissions were collected on filters, and then analyzed via nanospray desorption electrospray ionization–high-resolution mass spectrometry (nano-DESI-HRMS) and high-performance liquid chromatography–photodiode array–high-resolution mass spectrometry (HPLC-PDA-HRMS) techniques. The nano-DESI-HRMS analysis provided an inventory of numerous compounds present in the particle phase. Although several compounds observed in this study have been previously characterized using gas chromatography methods a majority of the species in the nano-DESI spectra were newly observed biomass burning compounds. Both the stove (chulha or angithi) and the fuel (brushwood or dung) affected the composition of organic aerosols. The geometric mean of the PM2.5 emission factor and the observed molecular complexity increased in the following order: brushwood–chulha (7.3 ± 1.8 g kg−1 dry fuel, 93 compounds), dung–chulha (21.1 ± 4.2 g kg−1 dry fuel, 212 compounds), and dung–angithi (29.8 ± 11.5 g kg−1 dry fuel, 262 compounds). The mass-normalized absorption coefficient (MACbulk) for the organic-solvent extractable material for brushwood PM2.5 was 3.7 ± 1.5 and 1.9 ± 0.8 m2 g−1 at 360 and 405 nm, respectively, which was approximately a factor of two higher than that for dung PM2.5. The HPLC-PDA-HRMS analysis showed that, regardless of fuel type, the main chromophores were CxHyOz lignin fragments. The main chromophores accounting for the higher MACbulk values of brushwood PM2.5 were C8H10O3 (tentatively assigned to syringol), nitrophenols C8H9NO4, and C10H10O3 (tentatively assigned to methoxycinnamic acid).

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