Solid-phase microextraction (SPME) was employed to determine sorption coefficients for pyrene on dissolved humic substances (D HS) of Various origins and also on model polymers to gain a better understanding of the relationships between sorption potential and sorbent structures. The sorption potential of DHS from very different sources is described by an empirical two-parameter correlation involving the polarity (O/H atomic ratio) and the aromaticity (epsilon (280nm)) as descriptors. On the other hand, sorption experiments with well-defined model polymers, poly(acrylic acid) esters, led to the conclusion that aliphatic chains may be more effective than aromatic moieties in binding PAHs. The molecular weight of the model sorbents was found to have a significant influence on the sorption potential.