Sorption of aquatic humic matter by DAX-8 and XAD-8 resins - Comparative study using pyrolysis gas chromatography

Aquatic humic solutes were separated in parallel by the non-ionic macroporous DAX-8 and XAD-8 resins from four different fresh water sources. The sorptive power of the DAX-8 resin was systematically somewhat greater compared to that of the XAD-8 resin. The DAX-8 resin seems to have more precise column characteristics compared with the XAD-8 resin. According to the tetramethylammonium hydroxide (TMAH) procedure followed up with pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) the content and quality of aliphatic carbons were the most systematic and powerful discriminating factors between the humic extracts obtained by these two resins. Generally speaking, the DAX-8 and XAD-8 resins seem to isolate humic solute bulks almost equally, although the content of aliphatics is slightly greater for the former, producing mixtures with similar structural compositions for general purposes. The environmental impact was also visible on the quality of the structural fine chemistry of the different humic isolates obtained both by the DAX-8 and XAD-8 resins. (C) 2002 Elsevier Science B.V. All rights reserved.