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Abstract: The effect of off-line alkylation using a powerful methylating reagent of carbanion and methyl iodide on the kind and yield of degradation products of humic and fulvic acids in their pyrolysis-gas chromatography (Py-GC) was examined. The humic and fulvic acids used were prepared from three soils including a Dystric Cambisol, an Umbric Andosol, and a Podzol. The yields of aliphatic and lignin-derived phenolic compounds did not increase or decreased generally after the off-line methylation in comparison with conventional thermally assisted hydrolysis and methylation (THM) using tetramethylammonium hydroxide (TMAH) for unmethylated samples. However, benzenetetracarboxylic acid tetramethyl esters and benzenepentacarboxylic acid pentamethyl ester became detectable or increased in yield for all the three fulvic acids examined and one humic acid sample characterized by its high concentration of carboxyl groups. Benzenehexacarboxylic acid hexamethyl ester was also detected in off-line methylated fulvic acids soluble in dichloromethane and purified with Sephadex LH-20. The addition of TMAH in pyrolysis of the off-line methylated samples did not improve the yields. Hence, the conventional THM comparatively lead to lower yields of the benzenepolycarboxylic acids (BPCAs) with 4–6 carboxyl groups, and the Py-GC after the off-line methylation could give additional information on structural unit of humic substances, although its single use did not increase total yields of degradation products. [Copyright &y& Elsevier]

Discusses the characterization of natural resin shellac by reactive pyrolysis-gas chromatography in the presence of organic alkali, tetramethylammonium hydroxide. Determination of terpenic acids, aleuritic acid, several minor fatty acids and wax components of shellac; Distribution of acidic components for shellac samples produced in India and Thailand.

Determines styrene copolymer sizing agents in paper by pyrolysis gas chromatography. Use of styrene monomer derived from the styrene sequences; Determination of the amounts of sizing agents retained in paper samples; Interpretation of the amounts of sizing agents in paper by degree of sizing.

Abstract: Conventional methods used to analyze total fatty acids in wood generally require tedious and time-consuming pretreatments such as solvent extraction and hydrolysis of esterified fatty acids of fats. In this study, both total fatty acid composition and the yield from free and esterified fatty acids of fats in Acacia species were investigated using a rapid and direct method of thermochemolysis–gas chromatography (GC)–flame ionization detector (FID)/mass spectrometry (MS) with organic alkalis. Using tetrabutylammonium hydroxide (TBAH) at 300°C, thermochemolysis–GC–FID/MS gave total fatty acids including the fat origin as pyrolyzates with suppressed lignin fragment formation because of the basicity of TBAH compared to other organic alkalis: tetramethylammonium hydroxide and tetramethylammonium acetate. The obtained results of fatty acid composition were consistent with those obtained using conventional methods consisting of a series of procedures such as solvent extraction, hydrolysis, derivatization, and analysis by GC–FID/MS in fatty acid composition analysis. Furthermore, thermochemolysis–GC–FID gave a higher yield of total fatty acid than the conventional method, quantitatively reflecting the difficulty in solvent extraction of these components. Consequently, thermochemolysis–GC with TBAH promises to be a rapid and direct method to characterize total fatty acids in wood, avoiding artifacts by solvent extraction of wood. Furthermore, this method discriminated Acacia auriculiformis from Acacia mangium based on the observed fatty acid contents and selected individuals containing low total fatty acids to minimize paper sliding on a printer drum. [Copyright &y& Elsevier]

Abstract: Copolymer composition of a biodegradable aliphatic copolyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) with a wide range of 3HV contents (ca. 4–23mol%) was determined by pyrolysis-gas chromatography (Py-GC) in the presence of tetramethylammonium hydroxide (TMAH). Nine major peaks of methylated products, five of which were attributed to the products from 3HV unit and the other four from 3HB unit, were commonly observed in the pyrograms. The copolymer compositions of P(3HB-co-3HV) samples estimated based on the relative intensities of these peaks were consistent with those by 1H NMR. These results demonstrated that Py-GC in the presence of TMAH can be applied to the accurate and highly sensitive compositional analysis of P(3HB-co-3HV) using trace amounts (ca. 0.1mg or less) of the samples. Furthermore, the fact that a small amount (ca. 1%) of the pyrolyzate from 3HV unit was also observed on the pyrogram of a commercially available poly(3-hydroxybutyrate), PHB, suggested that the given PHB might be actually a copolymer containing minor amount of 3HV unit. [Copyright &y& Elsevier]

Presents a quantitative analysis of detailed lignin monomer composition by pyrolysis-gas chromatography. Contribution of the lignin acetylation procedure; Determination of the dehydrogenative polymers; Accuracy of the preacetylation in analyzing the detailed lignin monomer composition.