Identification of bound alcohols in soil humic acids by gas chromatography-mass spectrometry

Humic acids are complex, partly macromolecular, yellow-brownish substances occurring in soils, waters and sediments. In order to shed some light on th eir molecular structure, crop humic acids were cleaved by alkaline hydrolys is (KOH), The products were fractionated by thin layer chromatography to gi ve mono-alcohols which were analysed as acetate derivatives by gas chromato graphy coupled to mass spectrometry, Linear alcohols, sterols, stanols and plant-derived triterpenoid alcohols were identified by co-injection of pure standards and by comparison with literature data. These findings imply tha t alcohols could have been incorporated into the humic matrix by esterifica tion with carboxylic acids. Furthermore, the presence of stanols as hydroge nated counterparts of sterols suggests that a process of hydrogenation is o perating in soils.