Characterization of high-molar-mass fractions in a Scots pine (Pinus sylvestris L.) knotwood ethanol extract
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Annika I. Smeds
,
Patrik C. Eklund
Abstract
The identification of compounds in Scots pine (Pinus sylvestris L.) knotwood (KnW), obtained by extracting with hydrophilic organic solvents, has been performed previously almost exclusively by gas chromatography-mass spectrometry (GS-MS) equipped with long GC columns (≥25 m). That means that the molar mass (MM) of the majority of the identified compounds was below 500–600 Da, and the analytical data accounted for only about half of the dry extract weight. In the present work, high-molar-mass (HMM) fractions in a Scots pine KnW-EtOH extract were isolated and chemically characterized by means of several advanced analytical techniques, such as high performance size-exclusion chromatography-evaporative light scattering detector (HPSEC-ELSD), high performance liquid chromatography (HPLC)-electrospray ionization-ion trap-mass spectrometry [(HPLC)ESI-IT-MS], ESI-quadrupole time of flight-mass spectrometry (QTOF-MS), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS), thermally assisted hydrolysis and methylation-gas chromatography-mass spectrometry (THM-GC-MS), nuclear magnetic resonance (NMR) and GC-MS. The results indicate that the MM maxima of the HMM fractions ranged from approximately 500 to 2200 Da, and that the compounds consist mainly of oligomers of hydroxylated resin acids (RAs), especially dehydroabietic acid, but also of fatty acids (FAs), stilbenes and sterols. A large number of RA dimers were tentatively identified in the HMM fractions. However, it remains unknown how the monomer units are linked together, as it was not possible to isolate a RA dimer fraction pure enough for NMR characterization. RA dimers in native KnW have not been identified previously.
Acknowledgments
This work is part of the activities at the Johan Gadolin Process Chemistry Centre, a Centre of Excellence financed by Åbo Akademi University.
Author contributions: All the authors have accepted responsibility for the entire content of this submitted manuscript and approved submission.
Research funding: None declared.
Employment or leadership: None declared.
Honorarium: None declared.
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Articles in the same Issue
- Frontmatter
- Original Articles
- The balance between alkali diffusion and alkali consuming reactions during impregnation of softwood. Impregnation for kraft pulping revisited
- Role of lignin and sodium carbonate on the swelling behavior of black liquor droplets during combustion
- Process optimization of lignin conversion into value added chemicals by thermochemical pretreatment and electrooxidation on a stainless steel anode
- Characterization of high-molar-mass fractions in a Scots pine (Pinus sylvestris L.) knotwood ethanol extract
- Discrimination of wood species based on a carbon nanotube/polymer composite chemiresistor array
- Characterization of moisture in acetylated and propionylated radiata pine using low-field nuclear magnetic resonance (LFNMR) relaxometry
- Effects of accelerated aging treatment on the microstructure and mechanics of wood-resin interphase
- Improved properties of thermally modified wood (TMW) by combined treatment with disodium octoborate tetrahydrate (DOT) and wax emulsion (WE)
- Liquid sorption, swelling and surface energy properties of unmodified and thermally modified Scots pine heartwood after extraction
Articles in the same Issue
- Frontmatter
- Original Articles
- The balance between alkali diffusion and alkali consuming reactions during impregnation of softwood. Impregnation for kraft pulping revisited
- Role of lignin and sodium carbonate on the swelling behavior of black liquor droplets during combustion
- Process optimization of lignin conversion into value added chemicals by thermochemical pretreatment and electrooxidation on a stainless steel anode
- Characterization of high-molar-mass fractions in a Scots pine (Pinus sylvestris L.) knotwood ethanol extract
- Discrimination of wood species based on a carbon nanotube/polymer composite chemiresistor array
- Characterization of moisture in acetylated and propionylated radiata pine using low-field nuclear magnetic resonance (LFNMR) relaxometry
- Effects of accelerated aging treatment on the microstructure and mechanics of wood-resin interphase
- Improved properties of thermally modified wood (TMW) by combined treatment with disodium octoborate tetrahydrate (DOT) and wax emulsion (WE)
- Liquid sorption, swelling and surface energy properties of unmodified and thermally modified Scots pine heartwood after extraction
