Characterisation of organic compounds in aerosol particles from a Finnish forest by on-line coupled supercritical fluid extraction?liquid chromatography?gas chromatography?mass spectrometry

Abstract

During the European Union project Quantification of Aerosol Nucleation in the European Boundary Layer (QUEST), which began in spring 2003, atmospheric aerosol particles were collected in a Finnish Scots pine forest using a high-volume sampler. The organic compounds in the filter samples were then analysed by on-line coupled supercritical fluid extraction-liquid chromatography-gas chromatography-mass spectrometry (SFE-LC-GC-MS). The sample was first extracted by SFE. During LC the extracts were fractionated into three fractions according to polarity. The final separation was carried out by GC-MS. A fraction volume as high as 840 microL was transferred to the GC, using the partial concurrent eluent evaporation technique. The same instrumentation, with an in-situ SFE derivatisation method, was used to analyse organic acids. Major compounds such as n-alkanes and PAH were analysed quantitatively. Their concentrations were lower than those usually observed in urban areas or in other forest areas in Europe. The wind direction was one of the most important factors affecting changes in the daily concentrations of these compounds. Scots pine needles were analysed with the same system to obtain reference data for identification of biogenic compounds in aerosol particles. Other organic compounds found in this study included hopanes, steranes, n-alkanals, n-alkan-2-ones, oxy-PAH, and alkyl-PAH; some biogenic products, including oxidation products of monoterpenes, were also identified.

Size and composition measurements of background aerosol and new particle growth in a Finnish forest during QUEST 2 using an Aerodyne Aerosol Mass Spectrometer

“…The most abundant alkanes also on non-polluted cases were in the range of C27-C29, which is taken to be indicative of biogenic sources of emission. Similar results were also obtained by the analyses of Shimmo et al (2004), who also found significant amounts of alkanes, with the peak at carbon number 27. Note that this carbon number cannot be directly confirmed using the AMS mass spectral data, as laboratory data have shown the locations and relative sizes of the peaks within the mass spectra to be largely invariant as a function of alkane carbon number (2003).…”

“…Alfarra et al, 2004;Topping et al, 2004). Other tracers for anthropogenic emissions were also detected under these conditions using offline techniques, for example polycyclic aromatic hydrocarbons and elemental carbon (Shimmo et al, 2004;R. Janson, Stockholm University, personal communication, 2005).…”

“…Aerosols were also collected on quartz filters using high-volume samplers for offline analysis at the Department of Chemistry, Helsinki, using techniques such as gas chromatography-mass spectrometry (GC-MS). For more information on the sampling methodology, the different types of organic analyses performed on the filter samples and the results obtained, the reader is directed to Anttila et al (2005), Shimmo et al (2004) and Rissanen et al (2006). Some of the particle physical data used in this publication were derived from instrumentation permanently deployed as part of the collocated Station for Measuring Forest Ecosystem-Atmosphere Relations (SMEAR) 2, in particular the Differential Mobility Particle Sizer (DMPS) system , which was used to count and size the particles between approximately 3 and 1000 nm on 10 min intervals.…”

Characterisation of solvent extractable organic constituents in atmospheric particulate matter: an overview

“…It is produced by thermal alteration and oxidation of phytol emitted from plants, or has a marine origin, and has been proposed as a marker for secondary biogenic aerosol (Abas et al 1995, Brown et al 2002, Gogou et al 1996, Simoneit et al 1988). This isoprenoid compound has been previously detected in an Abies forest of central Greece (Pio et al 2001a), rural aerosols from Crete (Gogou et al 1996), forest and rural locations of Portugal (Alves et al 2001(Alves et al , 2007Pio et al 2001b), a German urban/industrial influenced grassland location (Alves et al 2006), a coniferous forest in Germany (Plewka et al 2006), a Finnish boreal forest (Alves et al 2006, Shimmo et al 2004a), western United States (Simoneit and Mazurek 1982), Canada (Brown et al 2002, Cheng et al 2006, Amazonia (Abas et al 1995), Nigeria (Simoneit et al 1988) and Yosemite National Park (Engling et al 2006) at levels of dozens of ng m −3 .…”

“…However, the Los Angeles metropolitan area represents, incontestably, the one that is favoured by a higher number of studies on organic composition of atmospheric aerosols (Fine et al 2004b, Fraser et al 1997, Hildemann et al 1994, Lough et al 2006, Manchester-Neesvig et al 2003, Rinehart et al 2006, Rogge et al 1993e, 1996, Schauer et al 2002a, Simoneit 1984, Simoneit and Mazurek 1989, Zhu et al 2004. Comparatively, few studies have investigated remote, rural and semi-rural environments (Alves et al 2000, Cheng et al 2006, Feng et al 2007, Oliveira et al 2007b, Pio et al 2001a, b, Rissanen et al 2006, Shimmo et al 2004a, Simoneit et al 1990 or have been performed above ocean areas. These investigations include the Mediterranean (Gogou et al 1996, Grimalt et al 1988, Sicre et al 1987, Simó et al 1991, the North Pacific (Gagosian et al 1981, Kawamura 1995, the South Pacific (Gagosian et al 1987, Sicre andPeltzer 2004), the Caribbean (Mayol-Bracero et al 2001) and the Atlantic (Conte and Weber 2002, Simoneit and Elias 2000, Simoneit et al 1977, 1991b.…”