Characterisation of lignocellulose components by analytical pyrolysis gas chromatography mass spectrometry

Dissertation

Research output: ThesisDissertationCollection of Articles

Abstract

Analytical pyrolysis combined with gas chromatography mass spectrometry (Py-GC/MS) is a technique that can be used for the analysis of lignocellulose materials in situ. Pyrolysis degradation products provide information concerning the nature and origin of the initial sample. The main aim of this thesis was to apply analytical pyrolysis for lignin and carbohydrate characterisation from various lignocellulosic plant materials. Isothermal pyrolysis was the main technique utilised. In addition, thermochemolysis, thermal desorption and fractionated pyrolysis were applied in order to provide better understanding of the changes observed in lignin structure and carbohydrate composition in various materials and processes. In pyrolysis, hardwood lignin is degraded to guaiacyl and syringyl type pyrolysis degradation products with similar side chain structures, whereas carbohydrates form stable anhydrosugars. Lignin degradation products can be used to define the lignin composition and S/G ratio of the wood feedstocks. However, Py-GC/MS cannot be recommended for the comparison of carbohydrate composition between different wood species. Information on lignin structure and quantity was obtained directly from pulps by Py-GC/MS. Decrease of oxygenated lignin pyrolysis products and increase of short side chain structures were associated with beta-ether bond cleavage. Decrease of the short side chain structures as a function of delignification was interpreted to indicate leaching of the lignin products formed in cooking, and thus enrichment of native lignin in the residual pulp lignin. Due to the more complex chemical structure of brewers spent grain than of wood, its lignin composition was characterised by Py-GC/MS and thermochemolysis. Thermochemolysis results demonstrated that Py-GC/MS leads to underestimation of native type syringyl structures and S/G ratios. In addition, thermochemolysis with TMAAc and TMAH reagents was applied as a means to differentiate between free fatty acids and esters, respectively. The results showed that thermochemolysis with alkaline TMAH can be used to determine total fatty acid contents from the aliphatic and aromatic esters. TMAAc can be used to distinguish between free acids and aliphatic esters, but not between aromatic esters and free acids. In addition a thermal desorption method was developed to provide information on the odorous volatile organic compounds released from lignin. The method is applicable to the comparison of different lignin samples below their thermal degradation temperatures.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Vuorinen, Tapani, Supervisor, External person
  • Tamminen, Tarja, Advisor
Award date20 Dec 2017
Place of PublicationEspoo
Publisher
Print ISBNs978-952-60-7733-8, 978-951-38-8595-3
Electronic ISBNs978-952-60-7734-5, 978-951-38-8594-6
Publication statusPublished - 2017
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

Lignin
Gas chromatography
Mass spectrometry
Pyrolysis
Esters
Carbohydrates
Wood
Thermal desorption
Chemical analysis
Degradation
lignocellulose
Pulp
Fatty Acids
Volatile Organic Compounds
Delignification
Hardwoods
Cooking
Nonesterified Fatty Acids
Ether
Feedstocks

Keywords

  • Py-GC/MS
  • analysis
  • lignocellulose
  • lignin
  • carbohydrates

Cite this

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title = "Characterisation of lignocellulose components by analytical pyrolysis gas chromatography mass spectrometry: Dissertation",
abstract = "Analytical pyrolysis combined with gas chromatography mass spectrometry (Py-GC/MS) is a technique that can be used for the analysis of lignocellulose materials in situ. Pyrolysis degradation products provide information concerning the nature and origin of the initial sample. The main aim of this thesis was to apply analytical pyrolysis for lignin and carbohydrate characterisation from various lignocellulosic plant materials. Isothermal pyrolysis was the main technique utilised. In addition, thermochemolysis, thermal desorption and fractionated pyrolysis were applied in order to provide better understanding of the changes observed in lignin structure and carbohydrate composition in various materials and processes. In pyrolysis, hardwood lignin is degraded to guaiacyl and syringyl type pyrolysis degradation products with similar side chain structures, whereas carbohydrates form stable anhydrosugars. Lignin degradation products can be used to define the lignin composition and S/G ratio of the wood feedstocks. However, Py-GC/MS cannot be recommended for the comparison of carbohydrate composition between different wood species. Information on lignin structure and quantity was obtained directly from pulps by Py-GC/MS. Decrease of oxygenated lignin pyrolysis products and increase of short side chain structures were associated with beta-ether bond cleavage. Decrease of the short side chain structures as a function of delignification was interpreted to indicate leaching of the lignin products formed in cooking, and thus enrichment of native lignin in the residual pulp lignin. Due to the more complex chemical structure of brewers spent grain than of wood, its lignin composition was characterised by Py-GC/MS and thermochemolysis. Thermochemolysis results demonstrated that Py-GC/MS leads to underestimation of native type syringyl structures and S/G ratios. In addition, thermochemolysis with TMAAc and TMAH reagents was applied as a means to differentiate between free fatty acids and esters, respectively. The results showed that thermochemolysis with alkaline TMAH can be used to determine total fatty acid contents from the aliphatic and aromatic esters. TMAAc can be used to distinguish between free acids and aliphatic esters, but not between aromatic esters and free acids. In addition a thermal desorption method was developed to provide information on the odorous volatile organic compounds released from lignin. The method is applicable to the comparison of different lignin samples below their thermal degradation temperatures.",
keywords = "Py-GC/MS, analysis, lignocellulose, lignin, carbohydrates",
author = "Taina Ohra-aho",
year = "2017",
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series = "Aalto University publication series DOCTORAL DISSERTATIONS",
publisher = "Aalto University",
number = "230",
address = "Finland",
school = "Aalto University",

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Characterisation of lignocellulose components by analytical pyrolysis gas chromatography mass spectrometry : Dissertation. / Ohra-aho, Taina.

Espoo : Aalto University, 2017. 145 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Characterisation of lignocellulose components by analytical pyrolysis gas chromatography mass spectrometry

T2 - Dissertation

AU - Ohra-aho, Taina

PY - 2017

Y1 - 2017

N2 - Analytical pyrolysis combined with gas chromatography mass spectrometry (Py-GC/MS) is a technique that can be used for the analysis of lignocellulose materials in situ. Pyrolysis degradation products provide information concerning the nature and origin of the initial sample. The main aim of this thesis was to apply analytical pyrolysis for lignin and carbohydrate characterisation from various lignocellulosic plant materials. Isothermal pyrolysis was the main technique utilised. In addition, thermochemolysis, thermal desorption and fractionated pyrolysis were applied in order to provide better understanding of the changes observed in lignin structure and carbohydrate composition in various materials and processes. In pyrolysis, hardwood lignin is degraded to guaiacyl and syringyl type pyrolysis degradation products with similar side chain structures, whereas carbohydrates form stable anhydrosugars. Lignin degradation products can be used to define the lignin composition and S/G ratio of the wood feedstocks. However, Py-GC/MS cannot be recommended for the comparison of carbohydrate composition between different wood species. Information on lignin structure and quantity was obtained directly from pulps by Py-GC/MS. Decrease of oxygenated lignin pyrolysis products and increase of short side chain structures were associated with beta-ether bond cleavage. Decrease of the short side chain structures as a function of delignification was interpreted to indicate leaching of the lignin products formed in cooking, and thus enrichment of native lignin in the residual pulp lignin. Due to the more complex chemical structure of brewers spent grain than of wood, its lignin composition was characterised by Py-GC/MS and thermochemolysis. Thermochemolysis results demonstrated that Py-GC/MS leads to underestimation of native type syringyl structures and S/G ratios. In addition, thermochemolysis with TMAAc and TMAH reagents was applied as a means to differentiate between free fatty acids and esters, respectively. The results showed that thermochemolysis with alkaline TMAH can be used to determine total fatty acid contents from the aliphatic and aromatic esters. TMAAc can be used to distinguish between free acids and aliphatic esters, but not between aromatic esters and free acids. In addition a thermal desorption method was developed to provide information on the odorous volatile organic compounds released from lignin. The method is applicable to the comparison of different lignin samples below their thermal degradation temperatures.

AB - Analytical pyrolysis combined with gas chromatography mass spectrometry (Py-GC/MS) is a technique that can be used for the analysis of lignocellulose materials in situ. Pyrolysis degradation products provide information concerning the nature and origin of the initial sample. The main aim of this thesis was to apply analytical pyrolysis for lignin and carbohydrate characterisation from various lignocellulosic plant materials. Isothermal pyrolysis was the main technique utilised. In addition, thermochemolysis, thermal desorption and fractionated pyrolysis were applied in order to provide better understanding of the changes observed in lignin structure and carbohydrate composition in various materials and processes. In pyrolysis, hardwood lignin is degraded to guaiacyl and syringyl type pyrolysis degradation products with similar side chain structures, whereas carbohydrates form stable anhydrosugars. Lignin degradation products can be used to define the lignin composition and S/G ratio of the wood feedstocks. However, Py-GC/MS cannot be recommended for the comparison of carbohydrate composition between different wood species. Information on lignin structure and quantity was obtained directly from pulps by Py-GC/MS. Decrease of oxygenated lignin pyrolysis products and increase of short side chain structures were associated with beta-ether bond cleavage. Decrease of the short side chain structures as a function of delignification was interpreted to indicate leaching of the lignin products formed in cooking, and thus enrichment of native lignin in the residual pulp lignin. Due to the more complex chemical structure of brewers spent grain than of wood, its lignin composition was characterised by Py-GC/MS and thermochemolysis. Thermochemolysis results demonstrated that Py-GC/MS leads to underestimation of native type syringyl structures and S/G ratios. In addition, thermochemolysis with TMAAc and TMAH reagents was applied as a means to differentiate between free fatty acids and esters, respectively. The results showed that thermochemolysis with alkaline TMAH can be used to determine total fatty acid contents from the aliphatic and aromatic esters. TMAAc can be used to distinguish between free acids and aliphatic esters, but not between aromatic esters and free acids. In addition a thermal desorption method was developed to provide information on the odorous volatile organic compounds released from lignin. The method is applicable to the comparison of different lignin samples below their thermal degradation temperatures.

KW - Py-GC/MS

KW - analysis

KW - lignocellulose

KW - lignin

KW - carbohydrates

M3 - Dissertation

SN - 978-952-60-7733-8

SN - 978-951-38-8595-3

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

CY - Espoo

ER -