In analyzing the compounds in environmental samples, recovery is decreased by the effect of humic substances. The non-covalent interaction between the organic compounds and humic substances should be considered in analytical pervaporation. Analytical pervaporation through a PDMS membrane for environmental samples was investigated and evaluated by comparison to the pervaporation results for the model solution with added humic acids to clarify the non-covalent interaction. At pH 8.5, polar compounds were prevented from permeating into the membrane by the interactions; also, the flux decreased with increasing humic acid concentration. At pH 4, the non-covalent interactions of pi-pi interactions are predominant between solute compounds and humic acids. Fluorobenzene and 4-bromofluorobenzene, with a benzene ring, interacted with humic substances and the flux decreased. (C) 2003 Elsevier B.V. All rights reserved.