Talanta 55 (2001) 733–742 Comparisons of sorption of aquatic humic matter by DAX-8 and XAD-8 resins from solid-state 13 C NMR spectroscopy’s point of view Juhani Peuravuori a, *, Petri Ingman b , Kalevi Pihlaja a , Riitta Koivikko a a Department of Chemistry, Laboratory of Physical Chemistry, Uniersity of Turku, FIN-20014, Turku, Finland b Department of Physical Sciences, Uniersity of Oulu, FIN-90014, Oulu, Finland Received 20 April 2001; received in revised form 12 June 2001; accepted 15 June 2001 Abstract Aquatic humic solutes were separated in parallel by the non-ionic macroporous DAX-8 and XAD-8 resins from four different fresh water sources. On average, the sorptive power of the DAX-8 resin does not differ systematically from that of the XAD-8 resin. The DAX-8 resin seems to have more precise column characteristics compared with the XAD-8 resin. There was no significant difference between the major elemental compositions of the parallel humic-solute bulks obtained by these two resins. According to the 13 C NMR spectroscopy the content and quality of aliphatic carbons, especially those representing terminal methyl groups or methylene 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 structural composition and quantity of the humic-solute mixture isolable with a weakly basic DEAE-cellulose anion exchange resin differs partially from any humic fraction obtained by non-ionic sorbing solids. 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. © 2001 Elsevier Science B.V. All rights reserved. Keywords: DAX/XAD resin; Nuclear magnetic resonance (NMR); Humic substances; Structural composition www.elsevier.com/locate/talanta 1. Introduction The importance of macromolecular humic mat- ter (HM) in all aquatic natural systems is these days a consensus of opinion. The aquatic HM is present in water as dissolved molecules, as col- loidal suspensions, and as particulate matter. The dissolved phase has the main impact on the chem- istry and the biology of water. Thus the dissolved HM is the material which has received most inter- est. The filtered (mostly 0.45 m) water contains not only HM solutes but also other compounds of natural origin such as very hydrophilic low molec- ular acids, carbohydrates, fatty acids, amino acids * Corresponding author. Tel.: +358-2-333-6757; fax: + 358-2-333-6700. E-mail address: juhpeur@utu.fi (J. Peuravuori). 0039-9140/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved. PII:S0039-9140(01)00478-7