title: Partitioning of the pesticide trifluralin between dissolved organic matter and water using automated SPME-GC/MS.
abstract: Solid-phase microextraction (SPME) was used to determine the equilibrium association constant for a pesticide, trifluralin (TFR), with dissolved organic matter (DOM). After optimization of the SPME method for the analysis of TFR, partition coefficients (K DOM) with three different sources of DOM were determined in buffered solutions at pH 7. Commercial humic acids and DOM fractions isolated from two surface waters were used. The values of log K DOM varied from 4.3 to 5.8, depending on the nature of the organic material. A good correlation was established between log K DOM and DOM properties (as measured with the H/O atomic ratio and UV absorbance), in agreement with literature data. This is consistent with the effect of polarity and aromaticity for governing DOM-pollutant associations, regardless of the origin of DOM. This association phenomenon is relevant to better understand the behavior of pesticides in the environment since it controls part of pesticide leaching and fate in aquatic systems.
authors.affiliation: Université de Poitiers, CNRS-UMR 6008, Laboratoire de Chimie et Microbiologie de l'Eau, ENSIP, 86022, Poitiers, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Caupos
authors.forename: Arnaud
authors.initials: A
authors.lastname: Touffet
authors.forename: Patrick
authors.initials: P
authors.lastname: Mazellier
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Croue
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D006812:Humic Substances / Q000032:analysis; D010575:Pesticides / Q000032:analysis*; D052617:Solid Phase Microextraction; D014274:Trifluralin / Q000737:chemistry*; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D006812:Humic Substances; D010575:Pesticides; D014874:Water Pollutants, Chemical; D014867:Water; D014274:Trifluralin