Determination of organic acids in aerosol particles from a coniferous forest by liquid chromatography–mass spectrometry

Abstract

LC-MS methods with use of ion-trap and time-of-flight mass spectrometers were developed for the determination of organic acids in aerosol samples collected by a high-volume sampler in a Finnish coniferous forest. Comparison was made of the composition of samples collected during atmospheric formation of new aerosol particles and on days when this formation did not occur. A dynamic sonication-assisted solvent extraction system was developed for fast and quantitative extraction of the filter samples. Several organic acids, including pinonic acid, pinic acid, and homologous series of n-alkanoic acids, n-alkenoic acids, and aliphatic dicarboxylic acids, were identified. In samples collected between 08:00 and 16:00 hours the concentration of pinonic acid ranged from 0.5 ng m(-3) to 3.7 ng m(-3) and that of pinic acid from 0.2 ng m(-3) to 1.5 ng m(-3). For most of the compounds identified, the trends in concentration could be explained by the differences in temperature during collection. However, concentrations of short-chain n-alkanoic acids were clearly higher on the days when new aerosol particle formation occurred.

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

“…Other evidence of biogenic species in the particle phase (e.g. pinic acid and other tracers) was also observed during these periods (Anttila et al, 2005;Cavalli et al, 2005;R. Janson, Stockholm University, personal communication, 2005), but it is not clear based on the observations alone at what stage these species entered the particle phase; whether they condensed onto the particles within the local forest itself or further upwind.…”

“…Using Liquid Chromatography-MS on filter samples, Anttila et al (2005) made the finding that there was an increase in the amounts of short-chain n-alkanoic acids in the particles phase during event days. Monocarboxylic acids tend to give a large signal at m/z 43 in the AMS (Alfarra, 2004;Silva et al, 2006 1 ) and as this is the base peak during growth events, the finding is not inconsistent with the results presented here.…”

“…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.…”

The formation, properties and impact of secondary organic aerosol: current and emerging issues

“…LC is becoming increasingly popular for the analysis of polar compounds in aerosol and is routinely used for the analysis of carboxylic acids (Anttila et al, 2005;Römpp et al, 2006;Warnke et al, 2006). State-of-the art coupled LC/MS techniques (such as ion-trap, TOF and triple quadrupole MS) now offer similar or better detection limits than LC-fluorescence techniques and have improved greatly in terms of reliability, sensitivity and ease of use over the past 10 years.…”

α-pinene photooxidation under controlled chemical conditions – Part 2: SOA yield and composition in low- and high-NO<sub>x</sub> environments

“…A number of carboxylic acids have been used as particle-phase 7414 N. C. Eddingsaas et al: α-pinene photooxidation particle phase composition tracers of α-pinene oxidation, including pinonic acid, pinic acid, 10-hydroxypinonic acid, terpenylic acid, diaterpenylic acid acetate, and 3-methyl-1,2,3-butanetricarboxylic acid (3-MBTCA). For instance, pinonic and pinic acid have been observed to be in high concentration in aerosols collected in Portugal (accounting for 18-40 % of fine particle mass), in Greece (up to 26 % of fine particle mass), as well as in high yield in Finland (Kavouras et al, 1998(Kavouras et al, , 1999Anttila et al, 2005).…”