Development of a parallel sampling and analysis method for the elucidation of gas/particle partitioning of oxygenated semi-volatile organics: a limonene ozonolysis study

Abstract

The gas/particle partitioning behaviour of the semi-volatile fraction of secondary organic matter and the associated multiphase chemistry are key features to accurately evaluate climate and health impacts of secondary organic aerosol (SOA). However, today, the partitioning of oxygenated secondary species is rarely assessed in experimental SOA studies and SOA modelling is still largely based on estimated partitioning data. This paper describes a new analytical approach, solvent-free and easy to use, to explore the chemical composition of the secondary organic matter at a molecular scale in both gas and particulate phases. The method is based on thermal desorption (TD) of gas and particulate samples, coupled with gas chromatography (GC) and mass spectrometry (MS), with derivatisation on sampling supports. Gaseous compounds were trapped on Tenax TA adsorbent tubes pre-coated with pentafluorobenzylhydroxylamine (PFBHA) or N-Methyl-N-(<i>t</i>-butyldimethylsilyl)trifluoroacetamide (MTBSTFA). Particulate samples were collected onto quartz or Teflon-quartz filters and subsequently subjected to derivatisation with PFBHA or MTBSTFA before TD-GC/MS analysis. Method development and validation are presented for an atmospherically relevant range of organic acids and carbonyl and hydroxyl compounds. Application of the method to a limonene ozonolysis experiment conducted in the EUPHORE simulation chamber under simulated atmospheric conditions of low concentrations of limonene precursor and relative humidity, provides an overview of the method capabilities. Twenty-five compounds were positively or tentatively identified, nine being in both gaseous and particulate phases; and twelve, among them tricarboxylic acids, hydroxyl dicarboxylic acids and oxodicarboxylic acids, being detected for the first time

The Molecular Identification of Organic Compounds in the Atmosphere: State of the Art and Challenges

“…This is especially critical when investigating unknown and/or multi-functionalized compounds. In these cases, alternative approaches can be necessary such as the use of different derivatization procedures 222,242 on different samples in the same series, or the derivatization of different fractions of a sample that was first fractionated by flash chromatography 243 prior to GC/MS analysis. 244 More common approaches include multi-step derivatizations, which target the different hydroxyl, carboxylic acid, and/or keto-or aldehyde groups of multifunctional compounds.…”

Carboxylic acids from limonene oxidation by ozone and OH radicals: Insights into mechanisms derived using a FIGAERO-CIMS

“…Figure 2 shows an example of a mass spectrum from one of the experiments. Over 100 different molecular formulas for acids have been identified, far exceeding the number of acids reported in previous studies (Glasius et al, 2000;Leungsakul et al, 2005a;Jaoui et al, 2005Jaoui et al, , 2006Walser et al, 2008;Rossignol et al, 2012Rossignol et al, , 2013. Here we will focus on the analysis of acids with carbon numbers ranging from seven to ten (and the dimers formed from these acids).…”

“…Explicit formation pathways for the compounds C 10 H 16 O 4 and C 9 H 12 O 5 implemented in the MCM and additional reaction pathways for C 7 H 10 O 4 , C 8 H 12 O 4−5 , C 9 H 14 O 4−5 and C 10 H 16 O 3 are proposed. Structures for C 10 H 14 O 5 and C 10 H 16 O 4 have been proposed in previous studies (Glasius et al, 2000;Leungsakul et al, 2005a;Jaoui et al, 2006;Walser et al, 2008;Rossignol et al, 2012) but the current mechanistic understanding is inadequate for explaining the formation of compounds with the proposed structures. In fig.…”

FTIR gas kinetic study of the reactions of ozone with a series of hexenols at atmospheric pressure and 298K

“…The study of oxygenated volatile organic compounds (OVOCs) in the atmosphere of biogenic origin, and the degradation products resulting from their tropospheric oxidant mediated photooxidation, is of importance due to the high reactivity and ozone formation potential of many of these compounds which makes them substantial contributors to the formation of photochemical smog and secondary organic aerosol (SOA) 1 There have been a number of studies and evaluation of data on the reactions of ozone with unsaturated alcohols reported in the literature [4][5][6][7][8][9][10][11] . However, reactivity and mechanistic information for the reaction of ozone with the hexenols isomers is limited.…”