PYROLYSIS-GC-FTIR FOR STRUCTURAL ELUCIDATION OF AQUATIC HUMIC SUBSTANCES

Substructure components of various aquatic humic substances were inves tigated by a coupled pyrolysis - gas chromatography - Fourier-transfor m infrared spectroscopy (Py-GC-FTIR) procedure. The humic substances s tudied gave similar pyrolysis products, but in varying proportions. Ma ny of the pyrolysis products (e.g. methanol, acetone, alkylbenzenes, c yclopentane, aliphatic and aromatic organic acids, acetamide, pyrrole and phenols) could be identified by their FTIR spectra using a digital library for automatic comparison. Some of the compounds are related t o lignin fragments which form a large part of the humic substances inv estigated. Other products give hints to the involvement of tetrapyrrol es, fatty acids, furanoses and amino compounds in the structure of hum ic macromolecules.