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, ω-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 ω-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.