A new analytical procedure, tetramethylammonium hydroxide thermochemolysis, was used to structurally characterize a variety of bio- and geo-polymers. The technique cleaves esters and some ethers in macromolecular organic matter, yielding low-molecular-mass monomers such as methyl esters of carboxylic acids and methyl ethers of alcohols that are amenable to gas chromatographic analysis. This procedure can be conducted in sealed glass ampoules, which means that it can be easily implemented in any laboratory having gas chromatographic capabilities, in contrast to other chemolytic or pyrolytic procedures. A set of biogeomacromolecules, ranging from gymnosperm and angiosperm woods, natural polyesters such as cutin, dissolved organic matter in natural and oceanic waters, and humic substances were characterized with this procedure. The information obtained provides molecular-level details which can be used to infer structural composition. (C) 1998 Elsevier Science B.V. All rights reserved.