Buchanan, RM
1993
Thermogravimetry/Gas Chromatography/Mass Spectrometry and Thermogravimetry/Gas Chromatography/Fourier Transform Infrared Spectroscopy: Novel Hyphenated Methods in Thermal Analysis
McClennen, W.H.; Buchanan, R.M.; Arnold, N.S.; Dworzanski J.P. and Meuzelaar, H.L.C.
Analytical Chemistry, 65:2819-1823, 1993. Funded by Hewlett Packard and ACERC.
Two doubly hyphenated, thermogravimetry-based analytical techniques, viz. TG/GC/MS and TG/GC/IR, are described. A valveless, quartz, heated sample path between TG furnace and GC column minimizes losses of products. Furthermore, combination of a pulsed automated vapor-sampling inlet and a transfer line type GC column permits high-speed GC identification of individual TG products while maintaining sufficiently high temporal resolution with the ~1-min sampling interval to provide kinetic information about the underlying reaction mechanisms. Example analyses on poly (alpha-methylstyrene), a styrene-isoprene block copolymer, and wood demonstrate the techniques' capability for monitoring specific minor products and isomers.
1991
Examination of Coal by Combined Thermogravimetry/Infrared Spectroscopy/Mass Spectrometry
Buchanan, R.M.; Holbrook, K.M.; Meuzelaar, H.L.C. and Leibrand, R.
IRD Application Brief, Hewlett Packard, 23:5091-2022E, 1991.
Combined TG/IR and, to some extent, TG/MS techniques are finding increased application for structure/reactivity studies as well as for characterization and quality control of synthetic polymers, natural products, and fossil fuels. Unfortunately, the high cost of commercially available integrated TG/IR and TG/MS (let alone TG/IR/MS) systems has kept these techniques well out of reach for most analytical laboratories.
The advent of low cost bench-top FTIR and MS systems, however, has opened up the possibility of designing and assembling an affordable combined TG/FTIR/MS system. Such a system, developed at the University of Utah, Center for Micro Analysis, consists of a standard HP GC/IRD/MSD system utilizing an HP 5890 gas chromatograph, an HP 5965A IRD, and an HP 5971A MSD coupled to a Perkin Elmer Model 7 TG with a high temperature (1600? K max.) furnace. A specially constructed heated transfer line assembly allows direct coupling of the TG system to the GC injection port. The GC oven acts as a convenient heated coupling and flow distribution module. In this experiment no chromatography is performed with only sample transfer from the TG directly to the detectors.
Characterization of Lignocellulosic Materials and Model Compounds by Combined TG/(GC)/FTIR/MS
Dworzanski, J.P.; Buchanan, R.M.; Chapman, J.N. and Meuzelaar, H.L.C.
ASC Preprints, Division of Fuel Chemistry, 36(2):725-732, 1991 (201st ACS National Meeting, Atlanta, GA, April 1991). Funded by Pittsburgh Energy Technology Center/Consortium for Fossil Fuel Liquefaction, ACERC, Hewlett Packard Corp. and US Department of Energy.
Thermal analytical methods have been widely used during the last two decades in the study of biomass thermochemical conversion processes. Biomass, which represents a renewable energy resource, consists primarily of plant cells differentiated into characteristic tissues and organs. Lignins, hemicelluloses and cellulose, as the main components of the cell walls, were therefore extensively analyzed, especially from the point of view of their thermochemical reactivity, which is of basic importance for industrial processing of biomass.
All types of cellulose microfibrils are composed of linearly linked b-(1-->4)-D-glucopyranose units and differ only by the degree of polymerization. The remaining polysaccharides are known collectively as hemicelluloses and exhibit species related composition. These amorphous, complex heteropolymers characterized by a branched molecular structure exhibit a lower degree of polymerization than cellulose. Xylan is the predominant hemicellulose component of angiosperms ("hardwoods") whereas mannan forms the main hemicellulose of gymnosperms ("softwoods"). The third principal component of biomass, viz. lignin, is an irregular, high MW polymer formed by enzyme-initiated, free-radical polymerization of coniferyl alcohol (in hardwoods), coniferyl plus sinapyl alcohols (in softwoods), or coumaryl alcohol plus both above mentioned alcohols (in grasses). Lignins act as binding agents for the cellulose and hemicellulose fibers through a variety of linkages involving ether and carbon-carbon bonds of aromatic rings and propyl side chains.
Thermochemical conversion processes of lignocellulosic materials have been studied using mainly thermogravimetry (TG) or flash pyrolysis (Py) followed by gas chromatographic (GC) separation and identification of the reaction products. Modern analytical techniques based on coupled Py-GC/mass spectrometry (Py-GC/MS) or direct Py-MS as well as TG/MS or TG/infrared spectroscopy (TG/IR) have proved to be especially useful for elucidating the relationships between biomass structure and pyrolysis/devolatilization mechanisms.
A novel TG/(GC)/FTIR/MS system developed at the University of Utah, Center for Micro Analysis and Reaction Chemistry provides the opportunity for combining accurate weight loss measurements with precise information about composition and evolution rates of gaseous and liquid products as a function of temperature. In this paper, the usefulness of TG/FTIR/MS, TG/GC/MS and TG/GC/FTIR for thermochemical characterization of wood, lignins and cellulose will be discussed.
1990
A High Performance Thermogravimetry/Infrared Spectroscopy/Mass Spectrometry System Based on Standard Analytical Components
Holbrook, K.M.; Buchanan, R.M. and Meuzelaar, H.L.C.
Proc. of the 38th ASME Conference on Mass Spectrometry and Allied Topics, 900-901, Tucson, AZ, 1990. Funded by ACERC and Hewlett Packard Corp.
Combined TG/IR and, to some extent, TG/MS techniques are finding increased application for structure/reactivity studies as well as for characterization and quality control of synthetic polymers, fossil fuels and natural products. Unfortunately, the high cost of most integrated TG/MS and TG/IR (let alone TG/MS) systems has kept these techniques well out of reach for most analytical laboratories.
Buchanan, RM
1993
Thermogravimetry/Gas Chromatography/Mass Spectrometry and Thermogravimetry/Gas Chromatography/Fourier Transform Infrared Spectroscopy: Novel Hyphenated Methods in Thermal Analysis
McClennen, W.H.; Buchanan, R.M.; Arnold, N.S.; Dworzanski J.P. and Meuzelaar, H.L.C.
Analytical Chemistry, 65:2819-1823, 1993. Funded by Hewlett Packard and ACERC.
Two doubly hyphenated, thermogravimetry-based analytical techniques, viz. TG/GC/MS and TG/GC/IR, are described. A valveless, quartz, heated sample path between TG furnace and GC column minimizes losses of products. Furthermore, combination of a pulsed automated vapor-sampling inlet and a transfer line type GC column permits high-speed GC identification of individual TG products while maintaining sufficiently high temporal resolution with the ~1-min sampling interval to provide kinetic information about the underlying reaction mechanisms. Example analyses on poly (alpha-methylstyrene), a styrene-isoprene block copolymer, and wood demonstrate the techniques' capability for monitoring specific minor products and isomers.
1991
Examination of Coal by Combined Thermogravimetry/Infrared Spectroscopy/Mass Spectrometry
Buchanan, R.M.; Holbrook, K.M.; Meuzelaar, H.L.C. and Leibrand, R.
IRD Application Brief, Hewlett Packard, 23:5091-2022E, 1991.
Combined TG/IR and, to some extent, TG/MS techniques are finding increased application for structure/reactivity studies as well as for characterization and quality control of synthetic polymers, natural products, and fossil fuels. Unfortunately, the high cost of commercially available integrated TG/IR and TG/MS (let alone TG/IR/MS) systems has kept these techniques well out of reach for most analytical laboratories.
The advent of low cost bench-top FTIR and MS systems, however, has opened up the possibility of designing and assembling an affordable combined TG/FTIR/MS system. Such a system, developed at the University of Utah, Center for Micro Analysis, consists of a standard HP GC/IRD/MSD system utilizing an HP 5890 gas chromatograph, an HP 5965A IRD, and an HP 5971A MSD coupled to a Perkin Elmer Model 7 TG with a high temperature (1600? K max.) furnace. A specially constructed heated transfer line assembly allows direct coupling of the TG system to the GC injection port. The GC oven acts as a convenient heated coupling and flow distribution module. In this experiment no chromatography is performed with only sample transfer from the TG directly to the detectors.
Characterization of Lignocellulosic Materials and Model Compounds by Combined TG/(GC)/FTIR/MS
Dworzanski, J.P.; Buchanan, R.M.; Chapman, J.N. and Meuzelaar, H.L.C.
ASC Preprints, Division of Fuel Chemistry, 36(2):725-732, 1991 (201st ACS National Meeting, Atlanta, GA, April 1991). Funded by Pittsburgh Energy Technology Center/Consortium for Fossil Fuel Liquefaction, ACERC, Hewlett Packard Corp. and US Department of Energy.
Thermal analytical methods have been widely used during the last two decades in the study of biomass thermochemical conversion processes. Biomass, which represents a renewable energy resource, consists primarily of plant cells differentiated into characteristic tissues and organs. Lignins, hemicelluloses and cellulose, as the main components of the cell walls, were therefore extensively analyzed, especially from the point of view of their thermochemical reactivity, which is of basic importance for industrial processing of biomass.
All types of cellulose microfibrils are composed of linearly linked b-(1-->4)-D-glucopyranose units and differ only by the degree of polymerization. The remaining polysaccharides are known collectively as hemicelluloses and exhibit species related composition. These amorphous, complex heteropolymers characterized by a branched molecular structure exhibit a lower degree of polymerization than cellulose. Xylan is the predominant hemicellulose component of angiosperms ("hardwoods") whereas mannan forms the main hemicellulose of gymnosperms ("softwoods"). The third principal component of biomass, viz. lignin, is an irregular, high MW polymer formed by enzyme-initiated, free-radical polymerization of coniferyl alcohol (in hardwoods), coniferyl plus sinapyl alcohols (in softwoods), or coumaryl alcohol plus both above mentioned alcohols (in grasses). Lignins act as binding agents for the cellulose and hemicellulose fibers through a variety of linkages involving ether and carbon-carbon bonds of aromatic rings and propyl side chains.
Thermochemical conversion processes of lignocellulosic materials have been studied using mainly thermogravimetry (TG) or flash pyrolysis (Py) followed by gas chromatographic (GC) separation and identification of the reaction products. Modern analytical techniques based on coupled Py-GC/mass spectrometry (Py-GC/MS) or direct Py-MS as well as TG/MS or TG/infrared spectroscopy (TG/IR) have proved to be especially useful for elucidating the relationships between biomass structure and pyrolysis/devolatilization mechanisms.
A novel TG/(GC)/FTIR/MS system developed at the University of Utah, Center for Micro Analysis and Reaction Chemistry provides the opportunity for combining accurate weight loss measurements with precise information about composition and evolution rates of gaseous and liquid products as a function of temperature. In this paper, the usefulness of TG/FTIR/MS, TG/GC/MS and TG/GC/FTIR for thermochemical characterization of wood, lignins and cellulose will be discussed.
1990
A High Performance Thermogravimetry/Infrared Spectroscopy/Mass Spectrometry System Based on Standard Analytical Components
Holbrook, K.M.; Buchanan, R.M. and Meuzelaar, H.L.C.
Proc. of the 38th ASME Conference on Mass Spectrometry and Allied Topics, 900-901, Tucson, AZ, 1990. Funded by ACERC and Hewlett Packard Corp.
Combined TG/IR and, to some extent, TG/MS techniques are finding increased application for structure/reactivity studies as well as for characterization and quality control of synthetic polymers, fossil fuels and natural products. Unfortunately, the high cost of most integrated TG/MS and TG/IR (let alone TG/MS) systems has kept these techniques well out of reach for most analytical laboratories.