Abstract. Biogenic volatile organic compounds (BVOCs) emitted by terrestrial vegetation
participate in a diversity of natural processes. These compounds impact both
short-range processes, such as on plant protection and communication, and
long-range processes, for example by participating in aerosol particle formation
and growth. The biodiversity of plant species around the Earth, the vast
assortment of emitted BVOCs, and their trace atmospheric concentrations
contribute to the substantial remaining uncertainties about the effects of these
compounds on atmospheric chemistry and physics, and call for the development
of novel collection devices that can offer portability with improved
selectivity and capacity. In this study, a novel solid-phase microextraction
(SPME) Arrow sampling system was used for the static and dynamic collection
of BVOCs from a boreal forest, and samples were subsequently analyzed
on site by gas chromatography–mass spectrometry (GC-MS). This system offers
higher sampling capacity and improved robustness when compared to traditional
equilibrium-based SPME techniques, such as SPME fibers. Field measurements
were performed in summer 2017 at the Station for Measuring
Ecosystem–Atmosphere Relations (SMEAR II) in Hyytiälä, Finland.
Complementary laboratory tests were also performed to compare the SPME-based
techniques under controlled experimental conditions and to evaluate the
effect of temperature and relative humidity on their extraction performance.
The most abundant monoterpenes and aldehydes were successfully collected. A
significant improvement on sampling capacity was observed with the new SPME
Arrow system over SPME fibers, with collected amounts being approximately 2× higher for monoterpenes and 7–8× higher for aldehydes. BVOC
species exhibited different affinities for the type of sorbent materials used
(polydimethylsiloxane (PDMS)–carbon wide range (WR) vs. PDMS–divinylbenzene (DVB)). Higher extraction efficiencies were obtained
with dynamic collection prior to equilibrium regime, but this benefit during
the field measurements was small, probably due to the natural agitation
provided by the wind. An increase in temperature and relative humidity caused
a decrease in the amounts of analytes extracted under controlled experimental
conditions, even though the effect was more significant for PDMS–carbon WR
than for PDMS–DVB. Overall, results demonstrated the benefits and challenges
of using SPME Arrow for the sampling of BVOCs in the atmosphere.
Supplementary material to "Field measurements of biogenic volatile organic compounds in the atmosphere using solid-phase microextraction Arrow"
