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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 homologuous 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–3to 3.7 ng m–3and that of pinic acid from 0.2 ng m–3to 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.

Asymmetrical flow field‐flow fractionation (AsFlFFF) was used to determine the hydrodynamic particle sizes, molar masses, and phase transition behaviour of various poly(N‐isopropylacrylamide) (PNIPAM) samples synthesised by reversible addition–fragmentation chain transfer (RAFT) and conventional free radical polymerisation processes. The results were compared with corresponding data obtained by dynamic light scattering (DLS) and size exclusion chromatography (SEC). Agreement between the three methods was good except at higher molar masses, where the molar mass averages obtained by SEC were much lower than those obtained by AsFlFFF and light scattering. The aggregation of the polymers, which are thermally sensitive, was studied by DLS and AsFlFFF at various temperatures. In deionised water there was an abrupt change in the particle size due to phase separation at ≈32–35°C. The critical temperatures determined by AsFlFFF were 3–5°C higher than those obtained by DLS.

Comprehensive two-dimensional gas chromatography utilising a semi-rotating cryogenic modulator was applied to the analysis of dietary milk derived fatty acids. Four column combinations were tested: two polar-nonpolar and two different nonpolar-polar column combinations. Best results were obtained with a nonpolar-polar column set, with narrow-bore (50 μm ID) Carbowax column as the second column. The GC×GC method clearly improved the separation efficiency of the fatty acids in comparison with one-dimensional GC analysis and proved to be suitable for the quantification of the analytes. The relative standard deviations (RSD) of the retention times in the first and second dimensions were on average 0.06% and 4.9%, respectively. The relative RSD for peak volumes was on average 2.9%.

Comprehensive two‐dimensional gas chromatography utilising a semi‐rotating cryogenic modulator was applied to the analysis of dietary milk derived fatty acids. Four column combinations were tested: two polar‐nonpolar and two different nonpolar‐polar column combinations. Best results were obtained with a nonpolar‐polar column set, with narrow‐bore (50 μm ID) Carbowax column as the second column. The GC×GC method clearly improved the separation efficiency of the fatty acids in comparison with one‐dimensional GC analysis and proved to be suitable for the quantification of the analytes. The relative standard deviations (RSD) of the retention times in the first and second dimensions were on average 0.06% and 4.9%, respectively. The relative RSD for peak volumes was on average 2.9%.

The effect of different factors on the extraction yield in microporous membrane liquid-liquid extraction (MMLLE) was studied in this work. The factors were the extraction temperature, mixing of the donor and acceptor solvents, state of the acceptor (stagnant or flowing), solvent set-up in the membrane unit (organic phase on top or bottom), adsorption of the analytes into the membrane material, and the membrane pore size. The effect of temperature, as it was mediated through the other factors, was of particular interest. Increase in the extraction temperature improved the extraction yields substantially: for naphthalene the extraction yield increased from 14.3% to 17.7% and for benz[a]anthracene from 0.4% to 11.1% when the temperature was raised from 20°C to 80°C. The diffusion coefficients, which were determined with a chromatographic band broadening method, were also clearly increased with temperature: the average diffusion coefficient obtained for naphthalene in water at ambient temperature was 7.92×10^–10 m²/s, while at 70°C it was 2.19×10^–9 m²/s. The most vigorous mixing of the solvents was obtained with counter-currently flowing acceptor phase and water on top in the membrane block. The adsorption to the membrane material compared with theoretical 100% extraction yield ranged from 0.5 to 5.4% at 80°C when no acceptor phase was present.

Capillary zone electrophoresis of phenol and its three methyl-substituted derivatives (cresols) was investigated in water and methanol as solvents for the electrolyte. In water the acid strengths of o-cresol and p-cresol are too similar to allow their capillary zone electrophoretic separation. In pure methanol the differences in acid strength are amplified and all three cresols and phenol were clearly separated with use of pH 13–14 buffers prepared from maleic acid. The dependence of electrophoretic mobilities on pH in MeOH was investigated, and a slight difference was observed between theoretically calculated mobilities and measured mobilities. Maleate background electrolytes provided highly repeatable separations of the analytes. High pH medium in methanol appears to be a good choice for capillary zone electrophoretic separation of weak acids with similar acidity in water. The effective separation of 2,4-xylenol and 2,6-xylenol was also demonstrated.

Capillary zone electrophoresis of phenol and its three methyl‐substituted derivatives (cresols) was investigated in water and methanol as solvents for the electrolyte. In water the acid strengths of o‐cresol and p‐cresol are too similar to allow their capillary zone electrophoretic separation. In pure methanol the differences in acid strength are amplified and all three cresols and phenol were clearly separated with use of pH 13–14 buffers prepared from maleic acid. The dependence of electrophoretic mobilities on pH in MeOH was investigated, and a slight difference was observed between theoretically calculated mobilities and measured mobilities. Maleate background electrolytes provided highly repeatable separations of the analytes. High pH medium in methanol appears to be a good choice for capillary zone electrophoretic separation of weak acids with similar acidity in water. The effective separation of 2,4‐xylenol and 2,6‐xylenol was also demonstrated.

The effect of different factors on the extraction yield in microporous membrane liquid‐liquid extraction (MMLLE) was studied in this work. The factors were the extraction temperature, mixing of the donor and acceptor solvents, state of the acceptor (stagnant or flowing), solvent set‐up in the membrane unit (organic phase on top or bottom), adsorption of the analytes into the membrane material, and the membrane pore size. The effect of temperature, as it was mediated through the other factors, was of particular interest. Increase in the extraction temperature improved the extraction yields substantially: for naphthalene the extraction yield increased from 14.3% to 17.7% and for benz[a]anthracene from 0.4% to 11.1% when the temperature was raised from 20°C to 80°C. The diffusion coefficients, which were determined with a chromatographic band broadening method, were also clearly increased with temperature: the average diffusion coefficient obtained for naphthalene in water at ambient temperature was 7.92×10–10m2/s, while at 70°C it was 2.19×10–9m2/s. The most vigorous mixing of the solvents was obtained with counter‐currently flowing acceptor phase and water on top in the membrane block. The adsorption to the membrane material compared with theoretical 100% extraction yield ranged from 0.5 to 5.4% at 80°C when no acceptor phase was present.

Unilamellar liposomes were investigated by capillary electrophoresis, light scattering, and monolayer penetration techniques. Zwitterionic liposomes with and without cholesterol were compared and the effects of pH (7.40 and 8.25) and buffer (various sulfonic acid buffers, Tricine, and phosphate) on the electrophoretic mobilities and sizes of the liposomes were studied. Anionic liposomes containing phosphatidylserine with and without various amounts of cholesterol were used as dispersed phase in electrokinetic capillary chromatography in the separation of six steroidal hormones, with a focus on selectivity differences with increasing amounts of cholesterol in the liposomes. The results were confirmed by monolayer penetration measurements.

An efficient and fast method was developed for the determination of phenols in pyrolysis oils. Microporous membrane liquid‐liquid extraction (MMLLE) was applied in sample pretreatment and samples were analyzed by multidimensional liquid chromatography. The pyrolysis oil was dissolved in a suitable organic solvent and then continuously pumped through the donor side of the MMLLE system. The acceptor solution was a highly basic aqueous solution, which was kept stagnant during the extraction. The extract was transferred via a loop to the multidimensional LC system. Capillary electrophoresis was investigated for qualitative analysis of the extract. After separation, the phenols were identified by diode array detection and mass spectrometry. The method was quantitative, repeatable and linear, and limits of detection were in the range of 0.01–0.12%w/w.