A qualitative study on the chemical composition of ester-bound moieties in an acidic andosolic forest soil

Solvent insoluble ester-bound moieties, released after base treatment from an acidic andosolic forest soil A-horizon from Madeira, were sequentially extracted and analysed using gas chromatography and gas chromatography-mass spectrometry. The separation of all moieties released into several pH "subfractions" allowed the various products released to be studied in detail. The distributions obtained for 2-alkanols, diols, n-alkanols, n-alkanoic acids, omega-hydroxy acids, trihydroxy acids, dihydroxy diacids and phenolic acids indicate a suberin dominated origin of ester-related moieties in this andosolic soil A-horizon. However, a small contribution from plant cutins can not be ruled out completely. Besides plant biopolyesters, the detection of iso and anteiso alkanoic acids, together with short-chain di and omega-hydroxy acids suggests an additional bacterial-derived contribution. In addition to being attached to intact biopolyesters or molecules trapped in the insoluble organic macromolecular network present in soils, we suggest that hydroxy, n-alkanoic, aromatic and diacid moieties released upon base treatment of andosolic soils may occur as Al/Fe organic complexes. (C) 2002 Elsevier Science Ltd. All rights reserved.