High-Resolution Electrospray Ionization Mass Spectrometry Analysis of Water-Soluble Organic Aerosols Collected with a Particle into Liquid Sampler

Abstract

This work demonstrates the utility of a particle-into-liquid sampler (PILS), a technique traditionally used for identification of inorganic ions present in ambient or laboratory aerosols, for the analysis of water-soluble organic aerosol (OA) using high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). Secondary organic aerosol (SOA) was produced from 0.5 ppm mixing ratios of limonene and ozone in a 5 m(3) Teflon chamber. SOA was collected simultaneously using a traditional filter sampler and a PILS. The filter samples were later extracted with either water or acetonitrile, while the aqueous PILS samples were analyzed directly. In terms of peak abundances, types of detectable compounds, average O/C ratios, and organic mass to organic carbon ratios, the resulting high-resolution mass spectra were essentially identical for the PILS and filter based samples. SOA compounds extracted from both filter/acetonitrile extraction and PILS/water extraction accounted for >95% of the total ion current in the ESI mass spectra. This similarity was attributed to high solubility of limonene SOA in water. In contrast, significant differences in detected ions and peak abundances were observed for pine needle biomass burning organic aerosol (BBOA) collected with PILS and filter sampling. The water-soluble fraction of BBOA is considerably smaller than for SOA, and a number of unique peaks were detectable only by the filter/acetonitrile method. The combination of PILS collection with HR-ESI-MS analysis offers a new approach for molecular analysis of the water-soluble organic fraction in biogenic SOA, aged photochemical smog, and BBOA.

Water uptake is independent of the inferred composition of secondary aerosols derived from multiple biogenic VOCs

“…Compounds were removed from the list if they contained any H : C < 0.5, O : C > 3 or DBE > 20. Using the formulae, the intensity weighted mean O : C and H : C ratios of each sample were determined (Bateman et al, 2010) and these used to calculate the average carbon oxidation state (OS C ) according to Kroll et al (2011).…”

“…In this study, we have identified a subset of biogenic VOCs with an aim to represent a broad range of emitted species and the corresponding range in the rates and chemical complexity of their subsequent degradation. Based on the available information on the atmospheric lifetimes of observed biogenic VOCs with respect to reaction with OH radicals and O 3 , and current understanding of their known or probable degradation pathways, it is reasonable to divide the biogenic VOCs into a series of structural subsets possessing similar characteristics (Atkinson and Arey, 2003). As a result, consideration of a single compound from each category provides a reasonable starting point for simplifying the emitted speciation whilst maintaining the range in oxidation timescales and propensities to generate SOA.…”

“…Biogenic hydrocarbons are a dominant contributor to the global VOC budget and are known for their high reactivity towards the main atmospheric oxidants (e.g. hydroxyl radical, nitrate radical and ozone), which makes them major contributors to the total atmospheric burden of SOA (Atkinson and Arey, 2003;Kanakidou et al, 2005;Hallquist et al, 2009;Goldstein and Galbally, 2007). Understanding the formation and properties of biogenic SOA is a necessary step towards assessing the influence of atmospheric aerosols on major areas of concern such as climate change and human health.…”

Secondary organic aerosol formation from phenolic compounds in the absence of NO&lt;sub&gt;x&lt;/sub&gt;

“…www.atmos-chem-phys.net/11/10649/2011/ organic compounds (Bateman et al, 2010). In order to couple the PILS (Brechtel Manufacturing Inc.) to the TOFMS, the use of HPLC pumps in addition to a commonly used peristaltic pump was critical to overcome the backpressure of the TOFMS inlet and to supply steady flow of water (18.2 M , Milli-Q, Millipore) into the boiler.…”

Uncertainty Associated with the Analysis of Secondary Organic Aerosol Compounds Formed in Smog Chambers by Gas Chromatography-Mass Spectrometry

“…However, there is no single analytical method to analyze SOA products. In fact, each author develops own analytical methods, according to their needs (Forstner et al, 1997;Yu et al, 1998;Kleindienst et al, 2004;Chiappini et al, 2006;Bateman et al, 2010). Developing an analytical method is complex, long and rarely valued.…”